Publishing physical topology network locality for general workloads

ABSTRACT

Discussed herein are techniques that utilize hierarchical locality information of host machines included in a cluster network for the execution of general workloads. Hierarchical locality information for each host machine of a plurality of host machines is stored. The hierarchical locality information for a host machine identifying, for each locality of a plurality of localities, location information for the locality. Responsive to receiving a request requesting execution of a workload, the hierarchical locality information for the plurality of host machines is obtained and provided (e.g., to a customer) in response to the request.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a non-provisional of and claims the benefit of thefiling date, of U.S. Provisional Application No. 63/298,683, filed onJan. 12, 2022, the contents of which are incorporated herein byreference in its entirety for all purposes.

FIELD

The present disclosure relates to utilizing locality information of hostmachines included in a cloud infrastructure to execute workloads.

BACKGROUND

Organizations continue to move business applications and databases tothe cloud to reduce the cost of purchasing, updating, and maintainingon-premise hardware and software. High performance computingapplications consistently consume all of the available computing powerto achieve a specific outcome or result. Such applications requirededicated network performance, fast storage, high computingcapabilities, and significant amounts of memory-resources that are inshort supply in the virtualized infrastructure that constitutes today’scommodity clouds.

Cloud infrastructure service providers offer newer and faster graphicalprocessing units (GPUs) to address the requirements of theseapplications. A GPU workload is typically executed on one or more hostmachines. Typically, such workloads are not able to achieve an expectedlevel of throughput. One factor for this problem is the lack of flowentropy e.g., equal cost multi-path (ECMP) flow entropy. Furthermore,the problem is worsened by the fact that host machines (i.e., hosts)exchange traffic without regard for other hosts that are in their localnetwork neighborhood. Other types of workloads are typically executed byselecting one or more host machines from the infrastructure in a random(i.e., arbitrary) manner. In other words, the workloads are executedwithout considering the locality information (e.g., a physical locationof the host machine). As such, throughputs of these workloads are low.Embodiments discussed herein address these and other issues.

SUMMARY

The present disclosure relates generally to utilizing localityinformation of host machines included in a cloud infrastructure toexecute workloads. Various embodiments are described herein, includingmethods, systems, non-transitory computer-readable media storingprograms, code, or instructions executable by one or more processors,and the like. These illustrative embodiments are mentioned not to limitor define the disclosure, but to provide examples to aid understandingthereof. Additional embodiments are discussed in the detaileddescription section, and further description is provided therein.

One embodiment of the present disclosure is directed to a methodcomprising: storing, for each host machine of a plurality of hostmachines, hierarchical locality information for the host machine, thehierarchical locality information for a host machine identifying, foreach of a plurality of hierarchical levels, location information for thehost machine; and responsive to receiving a request requesting executionof a workload: obtaining the hierarchical locality information for theplurality of host machines, and providing the hierarchical localityinformation of the plurality of host machines as a response to therequest.

An aspect of the present disclosure provides for a system comprising oneor more data processors, and a non-transitory computer-readable storagemedium containing instructions which, when executed on the one or moredata processors, cause the one or more data processors to perform partor all of one or more methods disclosed herein.

Another aspect of the present disclosure provides for a computer-programproduct tangibly embodied in a non-transitory machine-readable storagemedium, including instructions configured to cause one or more dataprocessors to perform part or all of one or more methods disclosedherein.

The foregoing, together with other features and embodiments, will becomemore apparent upon referring to the following specification, claims, andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, embodiments, and advantages of the present disclosure arebetter understood when the following Detailed Description is read withreference to the accompanying drawings.

FIG. 1 is a high-level diagram of a distributed environment showing avirtual or overlay cloud network hosted by a cloud service providerinfrastructure, according to certain embodiments.

FIG. 2 depicts a simplified architectural diagram of the physicalcomponents in the physical network within CSPI, according to certainembodiments.

FIG. 3 shows an example arrangement within CSPI where a host machine isconnected to multiple network virtualization devices (NVDs), accordingto certain embodiments.

FIG. 4 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy, according tocertain embodiments.

FIG. 5 depicts a simplified block diagram of a physical network providedby a CSPI, according to certain embodiments.

FIG. 6 depicts a simplified block diagram of a cloud infrastructureincorporating a CLOS network arrangement, according to certainembodiments.

FIG. 7 illustrates an exemplary configuration of a rack included in thecloud infrastructure, according to certain embodiments.

FIG. 8 depicts a schematic illustrating a hierarchy of localityinformation, according to certain embodiments.

FIG. 9 illustrates an exemplary tree diagram illustrating differentlevels of locality information, according to certain embodiments.

FIG. 10 illustrates an exemplary encoded array of locality informationof a host machine, according to certain embodiments.

FIG. 11A illustrates an exemplary flowchart depicting steps performed inprovisioning a request, according to certain embodiments.

FIG. 11B illustrates another exemplary flowchart depicting stepsperformed in provisioning a customer’s workload request, according tocertain embodiments.

FIG. 12 is a block diagram illustrating one pattern for implementing acloud infrastructure as a service system, according to at least oneembodiment.

FIG. 13 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 14 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 15 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 16 is a block diagram illustrating an example computer system,according to at least one embodiment.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, specificdetails are set forth in order to provide a thorough understanding ofcertain embodiments. However, it will be apparent that variousembodiments may be practiced without these specific details. The figuresand description are not intended to be restrictive. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any embodiment or design described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother embodiments or designs.

Example Architecture of Cloud Infrastructure

The term cloud service is generally used to refer to a service that ismade available by a cloud services provider (CSP) to users or customerson demand (e.g., via a subscription model) using systems andinfrastructure (cloud infrastructure) provided by the CSP. Typically,the servers and systems that make up the CSP’s infrastructure areseparate from the customer’s own on-premise servers and systems.Customers can thus avail themselves of cloud services provided by theCSP without having to purchase separate hardware and software resourcesfor the services. Cloud services are designed to provide a subscribingcustomer easy, scalable access to applications and computing resourceswithout the customer having to invest in procuring the infrastructurethat is used for providing the services.

There are several cloud service providers that offer various types ofcloud services. There are various different types or models of cloudservices including Software-as-a-Service (SaaS), Platform-as-a-Service(PaaS), Infrastructure-as-a-Service (IaaS), and others.

A customer can subscribe to one or more cloud services provided by aCSP. The customer can be any entity such as an individual, anorganization, an enterprise, and the like. When a customer subscribes toor registers for a service provided by a CSP, a tenancy or an account iscreated for that customer. The customer can then, via this account,access the subscribed-to one or more cloud resources associated with theaccount.

As noted above, infrastructure as a service (IaaS) is one particulartype of cloud computing service. In an IaaS model, the CSP providesinfrastructure (referred to as cloud services provider infrastructure orCSPI) that can be used by customers to build their own customizablenetworks and deploy customer resources. The customer’s resources andnetworks are thus hosted in a distributed environment by infrastructureprovided by a CSP. This is different from traditional computing, wherethe customer’s resources and networks are hosted by infrastructureprovided by the customer.

The CSPI may comprise interconnected high-performance compute resourcesincluding various host machines, memory resources, and network resourcesthat form a physical network, which is also referred to as a substratenetwork or an underlay network. The resources in CSPI may be spreadacross one or more data centers that may be geographically spread acrossone or more geographical regions. Virtualization software may beexecuted by these physical resources to provide a virtualizeddistributed environment. The virtualization creates an overlay network(also known as a software-based network, a software-defined network, ora virtual network) over the physical network. The CSPI physical networkprovides the underlying basis for creating one or more overlay orvirtual networks on top of the physical network. The virtual or overlaynetworks can include one or more virtual cloud networks (VCNs). Thevirtual networks are implemented using software virtualizationtechnologies (e.g., hypervisors, functions performed by networkvirtualization devices (NVDs) (e.g., smartNICs), top-of-rack (TOR)switches, smart TORs that implement one or more functions performed byan NVD, and other mechanisms) to create layers of network abstractionthat can be run on top of the physical network. Virtual networks cantake on many forms, including peer-to-peer networks, IP networks, andothers. Virtual networks are typically either Layer-3 IP networks orLayer-2 VLANs. This method of virtual or overlay networking is oftenreferred to as virtual or overlay Layer-3 networking. Examples ofprotocols developed for virtual networks include IP-in-IP (or GenericRouting Encapsulation (GRE)), Virtual Extensible LAN (VXLAN - IETF RFC7348), Virtual Private Networks (VPNs) (e.g., MPLS Layer-3 VirtualPrivate Networks (RFC 4364)), VMware’s NSX, GENEVE (Generic NetworkVirtualization Encapsulation), and others.

For IaaS, the infrastructure (CSPI) provided by a CSP can be configuredto provide virtualized computing resources over a public network (e.g.,the Internet). In an IaaS model, a cloud computing services provider canhost the infrastructure components (e.g., servers, storage devices,network nodes (e.g., hardware), deployment software, platformvirtualization (e.g., a hypervisor layer), or the like). In some cases,an IaaS provider may also supply a variety of services to accompanythose infrastructure components (e.g., billing, monitoring, logging,security, load balancing and clustering, etc.). Thus, as these servicesmay be policy-driven, IaaS users may be able to implement policies todrive load balancing to maintain application availability andperformance. CSPI provides infrastructure and a set of complementarycloud services that enable customers to build and run a wide range ofapplications and services in a highly available hosted distributedenvironment. CSPI offers high-performance compute resources andcapabilities and storage capacity in a flexible virtual network that issecurely accessible from various networked locations such as from acustomer’s on-premises network. When a customer subscribes to orregisters for an IaaS service provided by a CSP, the tenancy created forthat customer is a secure and isolated partition within the CSPI wherethe customer can create, organize, and administer their cloud resources.

Customers can build their own virtual networks using compute, memory,and networking resources provided by CSPI. One or more customerresources or workloads, such as compute instances, can be deployed onthese virtual networks. For example, a customer can use resourcesprovided by CSPI to build one or multiple customizable and privatevirtual network(s) referred to as virtual cloud networks (VCNs). Acustomer can deploy one or more customer resources, such as computeinstances, on a customer VCN. Compute instances can take the form ofvirtual machines, bare metal instances, and the like. The CSPI thusprovides infrastructure and a set of complementary cloud services thatenable customers to build and run a wide range of applications andservices in a highly available virtual hosted environment. The customerdoes not manage or control the underlying physical resources provided byCSPI but has control over operating systems, storage, and deployedapplications; and possibly limited control of select networkingcomponents (e.g., firewalls).

The CSP may provide a console that enables customers and networkadministrators to configure, access, and manage resources deployed inthe cloud using CSPI resources. In certain embodiments, the consoleprovides a web-based user interface that can be used to access andmanage CSPI. In some implementations, the console is a web-basedapplication provided by the CSP.

CSPI may support single-tenancy or multi-tenancy architectures. In asingle tenancy architecture, a software (e.g., an application, adatabase) or a hardware component (e.g., a host machine or a server)serves a single customer or tenant. In a multi-tenancy architecture, asoftware or a hardware component serves multiple customers or tenants.Thus, in a multi-tenancy architecture, CSPI resources are shared betweenmultiple customers or tenants. In a multi-tenancy situation, precautionsare taken and safeguards put in place within CSPI to ensure that eachtenant’s data is isolated and remains invisible to other tenants.

In a physical network, a network endpoint (“endpoint”) refers to acomputing device or system that is connected to a physical network andcommunicates back and forth with the network to which it is connected. Anetwork endpoint in the physical network may be connected to a LocalArea Network (LAN), a Wide Area Network (WAN), or other type of physicalnetwork. Examples of traditional endpoints in a physical network includemodems, hubs, bridges, switches, routers, and other networking devices,physical computers (or host machines), and the like. Each physicaldevice in the physical network has a fixed network address that can beused to communicate with the device. This fixed network address can be aLayer-2 address (e.g., a MAC address), a fixed Layer-3 address (e.g., anIP address), and the like. In a virtualized environment or in a virtualnetwork, the endpoints can include various virtual endpoints such asvirtual machines that are hosted by components of the physical network(e.g., hosted by physical host machines). These endpoints in the virtualnetwork are addressed by overlay addresses such as overlay Layer-2addresses (e.g., overlay MAC addresses) and overlay Layer-3 addresses(e.g., overlay IP addresses). Network overlays enable flexibility byallowing network managers to move around the overlay addressesassociated with network endpoints using software management (e.g., viasoftware implementing a control plane for the virtual network).Accordingly, unlike in a physical network, in a virtual network, anoverlay address (e.g., an overlay IP address) can be moved from oneendpoint to another using network management software. Since the virtualnetwork is built on top of a physical network, communications betweencomponents in the virtual network involves both the virtual network andthe underlying physical network. In order to facilitate suchcommunications, the components of CSPI are configured to learn and storemappings that map overlay addresses in the virtual network to actualphysical addresses in the substrate network, and vice versa. Thesemappings are then used to facilitate the communications. Customertraffic is encapsulated to facilitate routing in the virtual network.

Accordingly, physical addresses (e.g., physical IP addresses) areassociated with components in physical networks and overlay addresses(e.g., overlay IP addresses) are associated with entities in virtualnetworks. Both the physical IP addresses and overlay IP addresses aretypes of real IP addresses. These are separate from virtual IPaddresses, where a virtual IP address maps to multiple real IPaddresses. A virtual IP address provides a 1-to-many mapping between thevirtual IP address and multiple real IP addresses.

The cloud infrastructure or CSPI is physically hosted in one or moredata centers in one or more regions around the world. The CSPI mayinclude components in the physical or substrate network and virtualizedcomponents (e.g., virtual networks, compute instances, virtual machines,etc.) that are in a virtual network built on top of the physical networkcomponents. In certain embodiments, the CSPI is organized and hosted inrealms, regions and availability domains. A region is typically alocalized geographic area that contains one or more data centers.Regions are generally independent of each other and can be separated byvast distances, for example, across countries or even continents. Forexample, a first region may be in Australia, another one in Japan, yetanother one in India, and the like. CSPI resources are divided amongregions such that each region has its own independent subset of CSPIresources. Each region may provide a set of core infrastructure servicesand resources, such as, compute resources (e.g., bare metal servers,virtual machine, containers and related infrastructure, etc.); storageresources (e.g., block volume storage, file storage, object storage,archive storage); networking resources (e.g., virtual cloud networks(VCNs), load balancing resources, connections to on-premise networks),database resources; edge networking resources (e.g., DNS); and accessmanagement and monitoring resources, and others. Each region generallyhas multiple paths connecting it to other regions in the realm.

Generally, an application is deployed in a region (i.e., deployed oninfrastructure associated with that region) where it is most heavilyused, because using nearby resources is faster than using distantresources. Applications can also be deployed in different regions forvarious reasons, such as redundancy to mitigate the risk of region-wideevents such as large weather systems or earthquakes, to meet varyingrequirements for legal jurisdictions, tax domains, and other business orsocial criteria, and the like.

The data centers within a region can be further organized and subdividedinto availability domains (ADs). An availability domain may correspondto one or more data centers located within a region. A region can becomposed of one or more availability domains. In such a distributedenvironment, CSPI resources are either region-specific, such as avirtual cloud network (VCN), or availability domain-specific, such as acompute instance.

ADs within a region are isolated from each other, fault tolerant, andare configured such that they are very unlikely to fail simultaneously.This is achieved by the ADs not sharing critical infrastructureresources such as networking, physical cables, cable paths, cable entrypoints, etc., such that a failure at one AD within a region is unlikelyto impact the availability of the other ADs within the same region. TheADs within the same region may be connected to each other by a lowlatency, high bandwidth network, which makes it possible to providehigh-availability connectivity to other networks (e.g., the Internet,customers’ on-premise networks, etc.) and to build replicated systems inmultiple ADs for both high-availability and disaster recovery. Cloudservices use multiple ADs to ensure high availability and to protectagainst resource failure. As the infrastructure provided by the IaaSprovider grows, more regions and ADs may be added with additionalcapacity. Traffic between availability domains is usually encrypted.

In certain embodiments, regions are grouped into realms. A realm is alogical collection of regions. Realms are isolated from each other anddo not share any data. Regions in the same realm may communicate witheach other, but regions in different realms cannot. A customer’s tenancyor account with the CSP exists in a single realm and can be spreadacross one or more regions that belong to that realm. Typically, when acustomer subscribes to an IaaS service, a tenancy or account is createdfor that customer in the customer-specified region (referred to as the“home” region) within a realm. A customer can extend the customer’stenancy across one or more other regions within the realm. A customercannot access regions that are not in the realm where the customer’stenancy exists.

An IaaS provider can provide multiple realms, each realm catered to aparticular set of customers or users. For example, a commercial realmmay be provided for commercial customers. As another example, a realmmay be provided for a specific country for customers within thatcountry. As yet another example, a government realm may be provided fora government, and the like. For example, the government realm may becatered for a specific government and may have a heightened level ofsecurity than a commercial realm. For example, Oracle CloudInfrastructure (OCI) currently offers a realm for commercial regions andtwo realms (e.g., FedRAMP authorized and IL5 authorized) for governmentcloud regions.

In certain embodiments, an AD can be subdivided into one or more faultdomains. A fault domain is a grouping of infrastructure resources withinan AD to provide anti-affinity. Fault domains allow for the distributionof compute instances such that the instances are not on the samephysical hardware within a single AD. This is known as anti-affinity. Afault domain refers to a set of hardware components (computers,switches, and more) that share a single point of failure. A compute poolis logically divided up into fault domains. Due to this, a hardwarefailure or compute hardware maintenance event that affects one faultdomain does not affect instances in other fault domains. Depending onthe embodiment, the number of fault domains for each AD may vary. Forinstance, in certain embodiments each AD contains three fault domains. Afault domain acts as a logical data center within an AD.

When a customer subscribes to an IaaS service, resources from CSPI areprovisioned for the customer and associated with the customer’s tenancy.The customer can use these provisioned resources to build privatenetworks and deploy resources on these networks. The customer networksthat are hosted in the cloud by the CSPI are referred to as virtualcloud networks (VCNs). A customer can set up one or more virtual cloudnetworks (VCNs) using CSPI resources allocated for the customer. A VCNis a virtual or software defined private network. The customer resourcesthat are deployed in the customer’s VCN can include compute instances(e.g., virtual machines, bare-metal instances) and other resources.These compute instances may represent various customer workloads such asapplications, load balancers, databases, and the like. A computeinstance deployed on a VCN can communicate with public accessibleendpoints (“public endpoints”) over a public network such as theInternet, with other instances in the same VCN or other VCNs (e.g., thecustomer’s other VCNs, or VCNs not belonging to the customer), with thecustomer’s on-premise data centers or networks, and with serviceendpoints, and other types of endpoints.

The CSP may provide various services using the CSPI. In some instances,customers of CSPI may themselves act like service providers and provideservices using CSPI resources. A service provider may expose a serviceendpoint, which is characterized by identification information (e.g., anIP Address, a DNS name and port). A customer’s resource (e.g., a computeinstance) can consume a particular service by accessing a serviceendpoint exposed by the service for that particular service. Theseservice endpoints are generally endpoints that are publicly accessibleby users using public IP addresses associated with the endpoints via apublic communication network such as the Internet. Network endpointsthat are publicly accessible are also sometimes referred to as publicendpoints.

In certain embodiments, a service provider may expose a service via anendpoint (sometimes referred to as a service endpoint) for the service.Customers of the service can then use this service endpoint to accessthe service. In certain implementations, a service endpoint provided fora service can be accessed by multiple customers that intend to consumethat service. In other implementations, a dedicated service endpoint maybe provided for a customer such that only that customer can access theservice using that dedicated service endpoint.

In certain embodiments, when a VCN is created, it is associated with aprivate overlay Classless Inter-Domain Routing (CIDR) address space,which is a range of private overlay IP addresses that are assigned tothe VCN (e.g., 10.0/16). A VCN includes associated subnets, routetables, and gateways. A VCN resides within a single region but can spanone or more or all of the region’s availability domains. A gateway is avirtual interface that is configured for a VCN and enables communicationof traffic to and from the VCN to one or more endpoints outside the VCN.One or more different types of gateways may be configured for a VCN toenable communication to and from different types of endpoints.

A VCN can be subdivided into one or more sub-networks such as one ormore subnets. A subnet is thus a unit of configuration or a subdivisionthat can be created within a VCN. A VCN can have one or multiplesubnets. Each subnet within a VCN is associated with a contiguous rangeof overlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN.

Each compute instance is associated with a virtual network interfacecard (VNIC) that enables the compute instance to participate in a subnetof a VCN. A VNIC is a logical representation of physical NetworkInterface Card (NIC). In general, a VNIC is an interface between anentity (e.g., a compute instance, a service) and a virtual network. AVNIC exists in a subnet, has one or more associated IP addresses, andassociated security rules or policies. A VNIC is equivalent to a Layer-2port on a switch. A VNIC is attached to a compute instance and to asubnet within a VCN. A VNIC associated with a compute instance enablesthe compute instance to be a part of a subnet of a VCN and enables thecompute instance to communicate (e.g., send and receive packets) withendpoints that are on the same subnet as the compute instance, withendpoints in different subnets in the VCN, or with endpoints outside theVCN. The VNIC associated with a compute instance thus determines how thecompute instance connects with endpoints inside and outside the VCN. AVNIC for a compute instance is created and associated with that computeinstance when the compute instance is created and added to a subnetwithin a VCN. For a subnet comprising a set of compute instances, thesubnet contains the VNICs corresponding to the set of compute instances,each VNIC attached to a compute instance within the set of computerinstances.

Each compute instance is assigned a private overlay IP address via theVNIC associated with the compute instance. This private overlay IPaddress is assigned to the VNIC that is associated with the computeinstance when the compute instance is created and used for routingtraffic to and from the compute instance. All VNICs in a given subnetuse the same route table, security lists, and DHCP options. As describedabove, each subnet within a VCN is associated with a contiguous range ofoverlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN. For a VNIC on aparticular subnet of a VCN, the private overlay IP address that isassigned to the VNIC is an address from the contiguous range of overlayIP addresses allocated for the subnet.

In certain embodiments, a compute instance may optionally be assignedadditional overlay IP addresses in addition to the private overlay IPaddress, such as, for example, one or more public IP addresses if in apublic subnet. These multiple addresses are assigned either on the sameVNIC or over multiple VNICs that are associated with the computeinstance. Each instance however has a primary VNIC that is createdduring instance launch and is associated with the overlay private IPaddress assigned to the instance—this primary VNIC cannot be removed.Additional VNICs, referred to as secondary VNICs, can be added to anexisting instance in the same availability domain as the primary VNIC.All the VNICs are in the same availability domain as the instance. Asecondary VNIC can be in a subnet in the same VCN as the primary VNIC,or in a different subnet that is either in the same VCN or a differentone.

A compute instance may optionally be assigned a public IP address if itis in a public subnet. A subnet can be designated as either a publicsubnet or a private subnet at the time the subnet is created. A privatesubnet means that the resources (e.g., compute instances) and associatedVNICs in the subnet cannot have public overlay IP addresses. A publicsubnet means that the resources and associated VNICs in the subnet canhave public IP addresses. A customer can designate a subnet to existeither in a single availability domain or across multiple availabilitydomains in a region or realm.

As described above, a VCN may be subdivided into one or more subnets. Incertain embodiments, a Virtual Router (VR) configured for the VCN(referred to as the VCN VR or just VR) enables communications betweenthe subnets of the VCN. For a subnet within a VCN, the VR represents alogical gateway for that subnet that enables the subnet (i.e., thecompute instances on that subnet) to communicate with endpoints on othersubnets within the VCN, and with other endpoints outside the VCN. TheVCN VR is a logical entity that is configured to route traffic betweenVNICs in the VCN and virtual gateways (“gateways”) associated with theVCN. Gateways are further described below with respect to FIG. 1 . A VCNVR is a Layer-3/IP Layer concept. In one embodiment, there is one VCN VRfor a VCN where the VCN VR has potentially an unlimited number of portsaddressed by IP addresses, with one port for each subnet of the VCN. Inthis manner, the VCN VR has a different IP address for each subnet inthe VCN that the VCN VR is attached to. The VR is also connected to thevarious gateways configured for a VCN. In certain embodiments, aparticular overlay IP address from the overlay IP address range for asubnet is reserved for a port of the VCN VR for that subnet. Forexample, consider a VCN having two subnets with associated addressranges 10.0/16 and 10.1/16, respectively. For the first subnet withinthe VCN with address range 10.0/16, an address from this range isreserved for a port of the VCN VR for that subnet. In some instances,the first IP address from the range may be reserved for the VCN VR. Forexample, for the subnet with overlay IP address range 10.0/16, IPaddress 10.0.0.1 may be reserved for a port of the VCN VR for thatsubnet. For the second subnet within the same VCN with address range10.1/16, the VCN VR may have a port for that second subnet with IPaddress 10.1.0.1. The VCN VR has a different IP address for each of thesubnets in the VCN.

In some other embodiments, each subnet within a VCN may have its ownassociated VR that is addressable by the subnet using a reserved ordefault IP address associated with the VR. The reserved or default IPaddress may, for example, be the first IP address from the range of IPaddresses associated with that subnet. The VNICs in the subnet cancommunicate (e.g., send and receive packets) with the VR associated withthe subnet using this default or reserved IP address. In such anembodiment, the VR is the ingress/egress point for that subnet. The VRassociated with a subnet within the VCN can communicate with other VRsassociated with other subnets within the VCN. The VRs can alsocommunicate with gateways associated with the VCN. The VR function for asubnet is running on or executed by one or more NVDs executing VNICsfunctionality for VNICs in the subnet.

Route tables, security rules, and DHCP options may be configured for aVCN. Route tables are virtual route tables for the VCN and include rulesto route traffic from subnets within the VCN to destinations outside theVCN by way of gateways or specially configured instances. A VCN’s routetables can be customized to control how packets are forwarded/routed toand from the VCN. DHCP options refers to configuration information thatis automatically provided to the instances when they boot up.

Security rules configured for a VCN represent overlay firewall rules forthe VCN. The security rules can include ingress and egress rules, andspecify the types of traffic (e.g., based upon protocol and port) thatis allowed in and out of the instances within the VCN. The customer canchoose whether a given rule is stateful or stateless. For instance, thecustomer can allow incoming SSH traffic from anywhere to a set ofinstances by setting up a stateful ingress rule with source CIDR0.0.0.0/0, and destination TCP port 22. Security rules can beimplemented using network security groups or security lists. A networksecurity group consists of a set of security rules that apply only tothe resources in that group. A security list, on the other hand,includes rules that apply to all the resources in any subnet that usesthe security list. A VCN may be provided with a default security listwith default security rules. DHCP options configured for a VCN provideconfiguration information that is automatically provided to theinstances in the VCN when the instances boot up.

In certain embodiments, the configuration information for a VCN isdetermined and stored by a VCN Control Plane. The configurationinformation for a VCN may include, for example, information about: theaddress range associated with the VCN, subnets within the VCN andassociated information, one or more VRs associated with the VCN, computeinstances in the VCN and associated VNICs, NVDs executing the variousvirtualization network functions (e.g., VNICs, VRs, gateways) associatedwith the VCN, state information for the VCN, and other VCN-relatedinformation. In certain embodiments, a VCN Distribution Servicepublishes the configuration information stored by the VCN Control Plane,or portions thereof, to the NVDs. The distributed information may beused to update information (e.g., forwarding tables, routing tables,etc.) stored and used by the NVDs to forward packets to and from thecompute instances in the VCN.

In certain embodiments, the creation of VCNs and subnets are handled bya VCN Control Plane (CP) and the launching of compute instances ishandled by a Compute Control Plane. The Compute Control Plane isresponsible for allocating the physical resources for the computeinstance and then calls the VCN Control Plane to create and attach VNICsto the compute instance. The VCN CP also sends VCN data mappings to theVCN data plane that is configured to perform packet forwarding androuting functions. In certain embodiments, the VCN CP provides adistribution service that is responsible for providing updates to theVCN data plane. Examples of a VCN Control Plane are also depicted inFIGS. 12, 13, 14, and 15 (see references 1216, 1316, 1416, and 1516) anddescribed below.

A customer may create one or more VCNs using resources hosted by CSPI. Acompute instance deployed on a customer VCN may communicate withdifferent endpoints. These endpoints can include endpoints that arehosted by CSPI and endpoints outside CSPI.

Various different architectures for implementing cloud-based serviceusing CSPI are depicted in FIGS. 1, 2, 3, 4, 5, 12, 13, 14, and 15 aredescribed below. FIG. 1 is a high level diagram of a distributedenvironment 100 showing an overlay or customer VCN hosted by CSPIaccording to certain embodiments. The distributed environment depictedin FIG. 1 includes multiple components in the overlay network.Distributed environment 100 depicted in FIG. 1 is merely an example andis not intended to unduly limit the scope of claimed embodiments. Manyvariations, alternatives, and modifications are possible. For example,in some implementations, the distributed environment depicted in FIG. 1may have more or fewer systems or components than those shown in FIG. 1, may combine two or more systems, or may have a different configurationor arrangement of systems.

As shown in the example depicted in FIG. 1 , distributed environment 100comprises CSPI 101 that provides services and resources that customerscan subscribe to and use to build their virtual cloud networks (VCNs).In certain embodiments, CSPI 101 offers IaaS services to subscribingcustomers. The data centers within CSPI 101 may be organized into one ormore regions. One example region “Region US” 102 is shown in FIG. 1 . Acustomer has configured a customer VCN 104 for region 102. The customermay deploy various compute instances on VCN 104, where the computeinstances may include virtual machines or bare metal instances. Examplesof instances include applications, database, load balancers, and thelike.

In the embodiment depicted in FIG. 1 , customer VCN 104 comprises twosubnets, namely, “Subnet-1” and “Subnet-2”, each subnet with its ownCIDR IP address range. In FIG. 1 , the overlay IP address range forSubnet-1 is 10.0/16 and the address range for Subnet-2 is 10.1/16. A VCNVirtual Router 105 represents a logical gateway for the VCN that enablescommunications between subnets of the VCN 104, and with other endpointsoutside the VCN. VCN VR 105 is configured to route traffic between VNICsin VCN 104 and gateways associated with VCN 104. VCN VR 105 provides aport for each subnet of VCN 104. For example, VR 105 may provide a portwith IP address 10.0.0.1 for Subnet-1 and a port with IP address10.1.0.1 for Subnet-2.

Multiple compute instances may be deployed on each subnet, where thecompute instances can be virtual machine instances, and/or bare metalinstances. The compute instances in a subnet may be hosted by one ormore host machines within CSPI 101. A compute instance participates in asubnet via a VNIC associated with the compute instance. For example, asshown in FIG. 1 , a compute instance C1 is part of Subnet-1 via a VNICassociated with the compute instance. Likewise, compute instance C2 ispart of Subnet-1 via a VNIC associated with C2. In a similar manner,multiple compute instances, which may be virtual machine instances orbare metal instances, may be part of Subnet-1. Via its associated VNIC,each compute instance is assigned a private overlay IP address and a MACaddress. For example, in FIG. 1 , compute instance C1 has an overlay IPaddress of 10.0.0.2 and a MAC address of M1, while compute instance C2has a private overlay IP address of 10.0.0.3 and a MAC address of M2.Each compute instance in Subnet-1, including compute instances C1 andC2, has a default route to VCN VR 105 using IP address 10.0.0.1, whichis the IP address for a port of VCN VR 105 for Subnet-1.

Subnet-2 can have multiple compute instances deployed on it, includingvirtual machine instances and/or bare metal instances. For example, asshown in FIG. 1 , compute instances D1 and D2 are part of Subnet-2 viaVNICs associated with the respective compute instances. In theembodiment depicted in FIG. 1 , compute instance D1 has an overlay IPaddress of 10.1.0.2 and a MAC address of MM1, while compute instance D2has a private overlay IP address of 10.1.0.3 and a MAC address of MM2.Each compute instance in Subnet-2, including compute instances D1 andD2, has a default route to VCN VR 105 using IP address 10.1.0.1, whichis the IP address for a port of VCN VR 105 for Subnet-2.

VCN A 104 may also include one or more load balancers. For example, aload balancer may be provided for a subnet and may be configured to loadbalance traffic across multiple compute instances on the subnet. A loadbalancer may also be provided to load balance traffic across subnets inthe VCN.

A particular compute instance deployed on VCN 104 can communicate withvarious different endpoints. These endpoints may include endpoints thatare hosted by CSPI 200 and endpoints outside CSPI 200. Endpoints thatare hosted by CSPI 101 may include: an endpoint on the same subnet asthe particular compute instance (e.g., communications between twocompute instances in Subnet-1); an endpoint on a different subnet butwithin the same VCN (e.g., communication between a compute instance inSubnet-1 and a compute instance in Subnet-2); an endpoint in a differentVCN in the same region (e.g., communications between a compute instancein Subnet-1 and an endpoint in a VCN in the same region 106 or 110,communications between a compute instance in Subnet-1 and an endpoint inservice network 110 in the same region); or an endpoint in a VCN in adifferent region (e.g., communications between a compute instance inSubnet-1 and an endpoint in a VCN in a different region 108). A computeinstance in a subnet hosted by CSPI 101 may also communicate withendpoints that are not hosted by CSPI 101 (i.e., are outside CSPI 101).These outside endpoints include endpoints in the customer’s on-premisenetwork 116, endpoints within other remote cloud hosted networks 118,public endpoints 114 accessible via a public network such as theInternet, and other endpoints.

Communications between compute instances on the same subnet arefacilitated using VNICs associated with the source compute instance andthe destination compute instance. For example, compute instance C1 inSubnet-1 may want to send packets to compute instance C2 in Subnet-1.For a packet originating at a source compute instance and whosedestination is another compute instance in the same subnet, the packetis first processed by the VNIC associated with the source computeinstance. Processing performed by the VNIC associated with the sourcecompute instance can include determining destination information for thepacket from the packet headers, identifying any policies (e.g., securitylists) configured for the VNIC associated with the source computeinstance, determining a next hop for the packet, performing any packetencapsulation/decapsulation functions as needed, and thenforwarding/routing the packet to the next hop with the goal offacilitating communication of the packet to its intended destination.When the destination compute instance is in the same subnet as thesource compute instance, the VNIC associated with the source computeinstance is configured to identify the VNIC associated with thedestination compute instance and forward the packet to that VNIC forprocessing. The VNIC associated with the destination compute instance isthen executed and forwards the packet to the destination computeinstance.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the communication isfacilitated by the VNICs associated with the source and destinationcompute instances and the VCN VR. For example, if compute instance C1 inSubnet-1 in FIG. 1 wants to send a packet to compute instance D1 inSubnet-2, the packet is first processed by the VNIC associated withcompute instance C1. The VNIC associated with compute instance C1 isconfigured to route the packet to the VCN VR 105 using default route orport 10.0.0.1 of the VCN VR. VCN VR 105 is configured to route thepacket to Subnet-2 using port 10.1.0.1. The packet is then received andprocessed by the VNIC associated with D1 and the VNIC forwards thepacket to compute instance D1.

For a packet to be communicated from a compute instance in VCN 104 to anendpoint that is outside VCN 104, the communication is facilitated bythe VNIC associated with the source compute instance, VCN VR 105, andgateways associated with VCN 104. One or more types of gateways may beassociated with VCN 104. A gateway is an interface between a VCN andanother endpoint, where the another endpoint is outside the VCN. Agateway is a Layer-3/IP layer concept and enables a VCN to communicatewith endpoints outside the VCN. A gateway thus facilitates traffic flowbetween a VCN and other VCNs or networks. Various different types ofgateways may be configured for a VCN to facilitate different types ofcommunications with different types of endpoints. Depending upon thegateway, the communications may be over public networks (e.g., theInternet) or over private networks. Various communication protocols maybe used for these communications.

For example, compute instance C1 may want to communicate with anendpoint outside VCN 104. The packet may be first processed by the VNICassociated with source compute instance C1. The VNIC processingdetermines that the destination for the packet is outside the Subnet-1of C1. The VNIC associated with C1 may forward the packet to VCN VR 105for VCN 104. VCN VR 105 then processes the packet and as part of theprocessing, based upon the destination for the packet, determines aparticular gateway associated with VCN 104 as the next hop for thepacket. VCN VR 105 may then forward the packet to the particularidentified gateway. For example, if the destination is an endpointwithin the customer’s on-premise network, then the packet may beforwarded by VCN VR 105 to Dynamic Routing Gateway (DRG) gateway 122configured for VCN 104. The packet may then be forwarded from thegateway to a next hop to facilitate communication of the packet to itfinal intended destination.

Various different types of gateways may be configured for a VCN.Examples of gateways that may be configured for a VCN are depicted inFIG. 1 and described below. Examples of gateways associated with a VCNare also depicted in FIGS. 12, 13, 14, and 15 (for example, gatewaysreferenced by reference numbers 1234, 1236, 1238, 1334, 1336, 1338,1434, 1436, 1438, 1534, 1536, and 1538) and described below. As shown inthe embodiment depicted in FIG. 1 , a Dynamic Routing Gateway (DRG) 122may be added to or be associated with customer VCN 104 and provides apath for private network traffic communication between customer VCN 104and another endpoint, where the another endpoint can be the customer’son-premise network 116, a VCN 108 in a different region of CSPI 101, orother remote cloud networks 118 not hosted by CSPI 101. Customeron-premise network 116 may be a customer network or a customer datacenter built using the customer’s resources. Access to customeron-premise network 116 is generally very restricted. For a customer thathas both a customer on-premise network 116 and one or more VCNs 104deployed or hosted in the cloud by CSPI 101, the customer may want theiron-premise network 116 and their cloud-based VCN 104 to be able tocommunicate with each other. This enables a customer to build anextended hybrid environment encompassing the customer’s VCN 104 hostedby CSPI 101 and their on-premises network 116. DRG 122 enables thiscommunication. To enable such communications, a communication channel124 is set up where one endpoint of the channel is in customeron-premise network 116 and the other endpoint is in CSPI 101 andconnected to customer VCN 104. Communication channel 124 can be overpublic communication networks such as the Internet or privatecommunication networks. Various different communication protocols may beused such as IPsec VPN technology over a public communication networksuch as the Internet, Oracle’s FastConnect technology that uses aprivate network instead of a public network, and others. The device orequipment in customer on-premise network 116 that forms one end pointfor communication channel 124 is referred to as the customer premiseequipment (CPE), such as CPE 126 depicted in FIG. 1 . On the CSPI 101side, the endpoint may be a host machine executing DRG 122.

In certain embodiments, a Remote Peering Connection (RPC) can be addedto a DRG, which allows a customer to peer one VCN with another VCN in adifferent region. Using such an RPC, customer VCN 104 can use DRG 122 toconnect with a VCN 108 in another region. DRG 122 may also be used tocommunicate with other remote cloud networks 118, not hosted by CSPI 101such as a Microsoft Azure cloud, Amazon AWS cloud, and others.

As shown in FIG. 1 , an Internet Gateway (IGW) 120 may be configured forcustomer VCN 104 the enables a compute instance on VCN 104 tocommunicate with public endpoints 114 accessible over a public networksuch as the Internet. IGW 1120 is a gateway that connects a VCN to apublic network such as the Internet. IGW 120 enables a public subnet(where the resources in the public subnet have public overlay IPaddresses) within a VCN, such as VCN 104, direct access to publicendpoints 112 on a public network 114 such as the Internet. Using IGW120, connections can be initiated from a subnet within VCN 104 or fromthe Internet.

A Network Address Translation (NAT) gateway 128 can be configured forcustomer’s VCN 104 and enables cloud resources in the customer’s VCN,which do not have dedicated public overlay IP addresses, access to theInternet and it does so without exposing those resources to directincoming Internet connections (e.g., L4-L7 connections). This enables aprivate subnet within a VCN, such as private Subnet-1 in VCN 104, withprivate access to public endpoints on the Internet. In NAT gateways,connections can be initiated only from the private subnet to the publicInternet and not from the Internet to the private subnet.

In certain embodiments, a Service Gateway (SGW) 126 can be configuredfor customer VCN 104 and provides a path for private network trafficbetween VCN 104 and supported services endpoints in a service network110. In certain embodiments, service network 110 may be provided by theCSP and may provide various services. An example of such a servicenetwork is Oracle’s Services Network, which provides various servicesthat can be used by customers. For example, a compute instance (e.g., adatabase system) in a private subnet of customer VCN 104 can back updata to a service endpoint (e.g., Object Storage) without needing publicIP addresses or access to the Internet. In certain embodiments, a VCNcan have only one SGW, and connections can only be initiated from asubnet within the VCN and not from service network 110. If a VCN ispeered with another, resources in the other VCN typically cannot accessthe SGW. Resources in on-premises networks that are connected to a VCNwith FastConnect or VPN Connect can also use the service gatewayconfigured for that VCN.

In certain implementations, SGW 126 uses the concept of a serviceClassless Inter-Domain Routing (CIDR) label, which is a string thatrepresents all the regional public IP address ranges for the service orgroup of services of interest. The customer uses the service CIDR labelwhen they configure the SGW and related route rules to control trafficto the service. The customer can optionally utilize it when configuringsecurity rules without needing to adjust them if the service’s public IPaddresses change in the future.

A Local Peering Gateway (LPG) 132 is a gateway that can be added tocustomer VCN 104 and enables VCN 104 to peer with another VCN in thesame region. Peering means that the VCNs communicate using private IPaddresses, without the traffic traversing a public network such as theInternet or without routing the traffic through the customer’son-premises network 116. In preferred embodiments, a VCN has a separateLPG for each peering it establishes. Local Peering or VCN Peering is acommon practice used to establish network connectivity between differentapplications or infrastructure management functions.

Service providers, such as providers of services in service network 110,may provide access to services using different access models. Accordingto a public access model, services may be exposed as public endpointsthat are publicly accessible by compute instance in a customer VCN via apublic network such as the Internet and or may be privately accessiblevia SGW 126. According to a specific private access model, services aremade accessible as private IP endpoints in a private subnet in thecustomer’s VCN. This is referred to as a Private Endpoint (PE) accessand enables a service provider to expose their service as an instance inthe customer’s private network. A Private Endpoint resource represents aservice within the customer’s VCN. Each PE manifests as a VNIC (referredto as a PE-VNIC, with one or more private IPs) in a subnet chosen by thecustomer in the customer’s VCN. A PE thus provides a way to present aservice within a private customer VCN subnet using a VNIC. Since theendpoint is exposed as a VNIC, all the features associates with a VNICsuch as routing rules, security lists, etc., are now available for thePE VNIC.

A service provider can register their service to enable access through aPE. The provider can associate policies with the service that restrictsthe service’s visibility to the customer tenancies. A provider canregister multiple services under a single virtual IP address (VIP),especially for multi-tenant services. There may be multiple such privateendpoints (in multiple VCNs) that represent the same service.

Compute instances in the private subnet can then use the PE VNIC’sprivate IP address or the service DNS name to access the service.Compute instances in the customer VCN can access the service by sendingtraffic to the private IP address of the PE in the customer VCN. APrivate Access Gateway (PAGW) 130 is a gateway resource that can beattached to a service provider VCN (e.g., a VCN in service network 110)that acts as an ingress/egress point for all traffic from/to customersubnet private endpoints. PAGW 130 enables a provider to scale thenumber of PE connections without utilizing its internal IP addressresources. A provider needs only configure one PAGW for any number ofservices registered in a single VCN. Providers can represent a serviceas a private endpoint in multiple VCNs of one or more customers. Fromthe customer’s perspective, the PE VNIC, which, instead of beingattached to a customer’s instance, appears attached to the service withwhich the customer wishes to interact. The traffic destined to theprivate endpoint is routed via PAGW 130 to the service. These arereferred to as customer-to-service private connections (C2Sconnections).

The PE concept can also be used to extend the private access for theservice to customer’s on-premises networks and data centers, by allowingthe traffic to flow through FastConnect/IPsec links and the privateendpoint in the customer VCN. Private access for the service can also beextended to the customer’s peered VCNs, by allowing the traffic to flowbetween LPG 132 and the PE in the customer’s VCN.

A customer can control routing in a VCN at the subnet level, so thecustomer can specify which subnets in the customer’s VCN, such as VCN104, use each gateway. A VCN’s route tables are used to decide iftraffic is allowed out of a VCN through a particular gateway. Forexample, in a particular instance, a route table for a public subnetwithin customer VCN 104 may send non-local traffic through IGW 120. Theroute table for a private subnet within the same customer VCN 104 maysend traffic destined for CSP services through SGW 126. All remainingtraffic may be sent via the NAT gateway 128. Route tables only controltraffic going out of a VCN.

Security lists associated with a VCN are used to control traffic thatcomes into a VCN via a gateway via inbound connections. All resources ina subnet use the same route table and security lists. Security lists maybe used to control specific types of traffic allowed in and out ofinstances in a subnet of a VCN. Security list rules may comprise ingress(inbound) and egress (outbound) rules. For example, an ingress rule mayspecify an allowed source address range, while an egress rule mayspecify an allowed destination address range. Security rules may specifya particular protocol (e.g., TCP, ICMP), a particular port (e.g., 22 forSSH, 3389 for Windows RDP), etc. In certain implementations, aninstance’s operating system may enforce its own firewall rules that arealigned with the security list rules. Rules may be stateful (e.g., aconnection is tracked and the response is automatically allowed withoutan explicit security list rule for the response traffic) or stateless.

Access from a customer VCN (i.e., by a resource or compute instancedeployed on VCN 104) can be categorized as public access, privateaccess, or dedicated access. Public access refers to an access modelwhere a public IP address or a NAT is used to access a public endpoint.Private access enables customer workloads in VCN 104 with private IPaddresses (e.g., resources in a private subnet) to access serviceswithout traversing a public network such as the Internet. In certainembodiments, CSPI 101 enables customer VCN workloads with private IPaddresses to access the (public service endpoints of) services using aservice gateway. A service gateway thus offers a private access model byestablishing a virtual link between the customer’s VCN and the service’spublic endpoint residing outside the customer’s private network.

Additionally, CSPI may offer dedicated public access using technologiessuch as FastConnect public peering where customer on-premises instancescan access one or more services in a customer VCN using a FastConnectconnection and without traversing a public network such as the Internet.CSPI also may also offer dedicated private access using FastConnectprivate peering where customer on-premises instances with private IPaddresses can access the customer’s VCN workloads using a FastConnectconnection. FastConnect is a network connectivity alternative to usingthe public Internet to connect a customer’s on-premise network to CSPIand its services. FastConnect provides an easy, elastic, and economicalway to create a dedicated and private connection with higher bandwidthoptions and a more reliable and consistent networking experience whencompared to Internet-based connections.

FIG. 1 and the accompanying description above describes variousvirtualized components in an example virtual network. As describedabove, the virtual network is built on the underlying physical orsubstrate network. FIG. 2 depicts a simplified architectural diagram ofthe physical components in the physical network within CSPI 200 thatprovide the underlay for the virtual network according to certainembodiments. As shown, CSPI 200 provides a distributed environmentcomprising components and resources (e.g., compute, memory, andnetworking resources) provided by a cloud service provider (CSP). Thesecomponents and resources are used to provide cloud services (e.g., IaaSservices) to subscribing customers, i.e., customers that have subscribedto one or more services provided by the CSP. Based upon the servicessubscribed to by a customer, a subset of resources (e.g., compute,memory, and networking resources) of CSPI 200 are provisioned for thecustomer. Customers can then build their own cloud-based (i.e.,CSPI-hosted) customizable and private virtual networks using physicalcompute, memory, and networking resources provided by CSPI 200. Aspreviously indicated, these customer networks are referred to as virtualcloud networks (VCNs). A customer can deploy one or more customerresources, such as compute instances, on these customer VCNs. Computeinstances can be in the form of virtual machines, bare metal instances,and the like. CSPI 200 provides infrastructure and a set ofcomplementary cloud services that enable customers to build and run awide range of applications and services in a highly available hostedenvironment.

In the example embodiment depicted in FIG. 2 , the physical componentsof CSPI 200 include one or more physical host machines or physicalservers (e.g., 202, 206, 208), network virtualization devices (NVDs)(e.g., 210, 212), top-of-rack (TOR) switches (e.g., 214, 216), and aphysical network (e.g., 218), and switches in physical network 218. Thephysical host machines or servers may host and execute various computeinstances that participate in one or more subnets of a VCN. The computeinstances may include virtual machine instances, and bare metalinstances. For example, the various compute instances depicted in FIG. 1may be hosted by the physical host machines depicted in FIG. 2 . Thevirtual machine compute instances in a VCN may be executed by one hostmachine or by multiple different host machines. The physical hostmachines may also host virtual host machines, container-based hosts orfunctions, and the like. The VNICs and VCN VR depicted in FIG. 1 may beexecuted by the NVDs depicted in FIG. 2 . The gateways depicted in FIG.1 may be executed by the host machines and/or by the NVDs depicted inFIG. 2 .

The host machines or servers may execute a hypervisor (also referred toas a virtual machine monitor or VMM) that creates and enables avirtualized environment on the host machines. The virtualization orvirtualized environment facilitates cloud-based computing. One or morecompute instances may be created, executed, and managed on a hostmachine by a hypervisor on that host machine. The hypervisor on a hostmachine enables the physical computing resources of the host machine(e.g., compute, memory, and networking resources) to be shared betweenthe various compute instances executed by the host machine.

For example, as depicted in FIG. 2 , host machines 202 and 208 executehypervisors 260 and 266, respectively. These hypervisors may beimplemented using software, firmware, or hardware, or combinationsthereof. Typically, a hypervisor is a process or a software layer thatsits on top of the host machine’s operating system (OS), which in turnexecutes on the hardware processors of the host machine. The hypervisorprovides a virtualized environment by enabling the physical computingresources (e.g., processing resources such as processors/cores, memoryresources, networking resources) of the host machine to be shared amongthe various virtual machine compute instances executed by the hostmachine. For example, in FIG. 2 , hypervisor 260 may sit on top of theOS of host machine 202 and enables the computing resources (e.g.,processing, memory, and networking resources) of host machine 202 to beshared between compute instances (e.g., virtual machines) executed byhost machine 202. A virtual machine can have its own operating system(referred to as a guest operating system), which may be the same as ordifferent from the OS of the host machine. The operating system of avirtual machine executed by a host machine may be the same as ordifferent from the operating system of another virtual machine executedby the same host machine. A hypervisor thus enables multiple operatingsystems to be executed alongside each other while sharing the samecomputing resources of the host machine. The host machines depicted inFIG. 2 may have the same or different types of hypervisors.

A compute instance can be a virtual machine instance or a bare metalinstance. In FIG. 2 , compute instances 268 on host machine 202 and 274on host machine 208 are examples of virtual machine instances. Hostmachine 206 is an example of a bare metal instance that is provided to acustomer.

In certain instances, an entire host machine may be provisioned to asingle customer, and all of the one or more compute instances (eithervirtual machines or bare metal instance) hosted by that host machinebelong to that same customer. In other instances, a host machine may beshared between multiple customers (i.e., multiple tenants). In such amulti-tenancy scenario, a host machine may host virtual machine computeinstances belonging to different customers. These compute instances maybe members of different VCNs of different customers. In certainembodiments, a bare metal compute instance is hosted by a bare metalserver without a hypervisor. When a bare metal compute instance isprovisioned, a single customer or tenant maintains control of thephysical CPU, memory, and network interfaces of the host machine hostingthe bare metal instance and the host machine is not shared with othercustomers or tenants.

As previously described, each compute instance that is part of a VCN isassociated with a VNIC that enables the compute instance to become amember of a subnet of the VCN. The VNIC associated with a computeinstance facilitates the communication of packets or frames to and fromthe compute instance. A VNIC is associated with a compute instance whenthe compute instance is created. In certain embodiments, for a computeinstance executed by a host machine, the VNIC associated with thatcompute instance is executed by an NVD connected to the host machine.For example, in FIG. 2 , host machine 202 executes a virtual machinecompute instance 268 that is associated with VNIC 276, and VNIC 276 isexecuted by NVD 210 connected to host machine 202. As another example,bare metal instance 272 hosted by host machine 206 is associated withVNIC 280 that is executed by NVD 212 connected to host machine 206. Asyet another example, VNIC 284 is associated with compute instance 274executed by host machine 208, and VNIC 284 is executed by NVD 212connected to host machine 208.

For compute instances hosted by a host machine, an NVD connected to thathost machine also executes VCN VRs corresponding to VCNs of which thecompute instances are members. For example, in the embodiment depictedin FIG. 2 , NVD 210 executes VCN VR 277 corresponding to the VCN ofwhich compute instance 268 is a member. NVD 212 may also execute one ormore VCN VRs 283 corresponding to VCNs corresponding to the computeinstances hosted by host machines 206 and 208.

A host machine may include one or more network interface cards (NIC)that enable the host machine to be connected to other devices. A NIC ona host machine may provide one or more ports (or interfaces) that enablethe host machine to be communicatively connected to another device. Forexample, a host machine may be connected to an NVD using one or moreports (or interfaces) provided on the host machine and on the NVD. Ahost machine may also be connected to other devices such as another hostmachine.

For example, in FIG. 2 , host machine 202 is connected to NVD 210 usinglink 220 that extends between a port 234 provided by a NIC 232 of hostmachine 202 and between a port 236 of NVD 210. Host machine 206 isconnected to NVD 212 using link 224 that extends between a port 246provided by a NIC 244 of host machine 206 and between a port 248 of NVD212. Host machine 208 is connected to NVD 212 using link 226 thatextends between a port 252 provided by a NIC 250 of host machine 208 andbetween a port 254 of NVD 212.

The NVDs are in turn connected via communication links totop-of-the-rack (TOR) switches, which are connected to physical network218 (also referred to as the switch fabric). In certain embodiments, thelinks between a host machine and an NVD, and between an NVD and a TORswitch are Ethernet links. For example, in FIG. 2 , NVDs 210 and 212 areconnected to TOR switches 214 and 216, respectively, using links 228 and230. In certain embodiments, the links 220, 224, 226, 228, and 230 areEthernet links. The collection of host machines and NVDs that areconnected to a TOR is sometimes referred to as a rack.

Physical network 218 provides a communication fabric that enables TORswitches to communicate with each other. Physical network 218 can be amulti-tiered network. In certain implementations, physical network 218is a multi-tiered Clos network of switches, with TOR switches 214 and216 representing the leaf level nodes of the multi-tiered and multi-nodephysical switching network 218. Different Clos network configurationsare possible including but not limited to a 2-tier network, a 3-tiernetwork, a 4-tier network, a 5-tier network, and in general a “n″-tierednetwork. An example of a Clos network is depicted in FIG. 5 anddescribed below.

Various different connection configurations are possible between hostmachines and NVDs such as one-to-one configuration, many-to-oneconfiguration, one-to-many configuration, and others. In a one-to-oneconfiguration implementation, each host machine is connected to its ownseparate NVD. For example, in FIG. 2 , host machine 202 is connected toNVD 210 via NIC 232 of host machine 202. In a many-to-one configuration,multiple host machines are connected to one NVD. For example, in FIG. 2, host machines 206 and 208 are connected to the same NVD 212 via NICs244 and 250, respectively.

In a one-to-many configuration, one host machine is connected tomultiple NVDs. FIG. 3 shows an example within CSPI 300 where a hostmachine is connected to multiple NVDs. As shown in FIG. 3 , host machine302 comprises a network interface card (NIC) 304 that includes multipleports 306 and 308. Host machine 300 is connected to a first NVD 310 viaport 306 and link 320, and connected to a second NVD 312 via port 308and link 322. Ports 306 and 308 may be Ethernet ports and the links 320and 322 between host machine 302 and NVDs 310 and 312 may be Ethernetlinks. NVD 310 is in turn connected to a first TOR switch 314 and NVD312 is connected to a second TOR switch 316. The links between NVDs 310and 312, and TOR switches 314 and 316 may be Ethernet links. TORswitches 314 and 316 represent the Tier-0 switching devices inmulti-tiered physical network 318.

The arrangement depicted in FIG. 3 provides two separate physicalnetwork paths to and from physical switch network 318 to host machine302: a first path traversing TOR switch 314 to NVD 310 to host machine302, and a second path traversing TOR switch 316 to NVD 312 to hostmachine 302. The separate paths provide for enhanced availability(referred to as high availability) of host machine 302. If there areproblems in one of the paths (e.g., a link in one of the paths goesdown) or devices (e.g., a particular NVD is not functioning), then theother path may be used for communications to/from host machine 302.

In the configuration depicted in FIG. 3 , the host machine is connectedto two different NVDs using two different ports provided by a NIC of thehost machine. In other embodiments, a host machine may include multipleNICs that enable connectivity of the host machine to multiple NVDs.

Referring back to FIG. 2 , an NVD is a physical device or component thatperforms one or more network and/or storage virtualization functions. AnNVD may be any device with one or more processing units (e.g., CPUs,Network Processing Units (NPUs), FPGAs, packet processing pipelines,etc.), memory including cache, and ports. The various virtualizationfunctions may be performed by software/firmware executed by the one ormore processing units of the NVD.

An NVD may be implemented in various different forms. For example, incertain embodiments, an NVD is implemented as an interface card referredto as a smartNIC or an intelligent NIC with an embedded processoronboard. A smartNIC is a separate device from the NICs on the hostmachines. In FIG. 2 , the NVDs 210 and 212 may be implemented assmartNICs that are connected to host machines 202, and host machines 206and 208, respectively.

A smartNIC is however just one example of an NVD implementation. Variousother implementations are possible. For example, in some otherimplementations, an NVD or one or more functions performed by the NVDmay be incorporated into or performed by one or more host machines, oneor more TOR switches, and other components of CSPI 200. For example, anNVD may be embodied in a host machine where the functions performed byan NVD are performed by the host machine. As another example, an NVD maybe part of a TOR switch or a TOR switch may be configured to performfunctions performed by an NVD that enables the TOR switch to performvarious complex packet transformations that are used for a public cloud.A TOR that performs the functions of an NVD is sometimes referred to asa smart TOR. In yet other implementations, where virtual machines (VMs)instances, but not bare metal (BM) instances, are offered to customers,functions performed by an NVD may be implemented inside a hypervisor ofthe host machine. In some other implementations, some of the functionsof the NVD may be offloaded to a centralized service running on a fleetof host machines.

In certain embodiments, such as when implemented as a smartNIC as shownin FIG. 2 , an NVD may comprise multiple physical ports that enable itto be connected to one or more host machines and to one or more TORswitches. A port on an NVD can be classified as a host-facing port (alsoreferred to as a “south port”) or a network-facing or TOR-facing port(also referred to as a “north port”). A host-facing port of an NVD is aport that is used to connect the NVD to a host machine. Examples ofhost-facing ports in FIG. 2 include port 236 on NVD 210, and ports 248and 254 on NVD 212. A network-facing port of an NVD is a port that isused to connect the NVD to a TOR switch. Examples of network-facingports in FIG. 2 include port 256 on NVD 210, and port 258 on NVD 212. Asshown in FIG. 2 , NVD 210 is connected to TOR switch 214 using link 228that extends from port 256 of NVD 210 to the TOR switch 214. Likewise,NVD 212 is connected to TOR switch 216 using link 230 that extends fromport 258 of NVD 212 to the TOR switch 216.

An NVD receives packets and frames from a host machine (e.g., packetsand frames generated by a compute instance hosted by the host machine)via a host-facing port and, after performing the necessary packetprocessing, may forward the packets and frames to a TOR switch via anetwork-facing port of the NVD. An NVD may receive packets and framesfrom a TOR switch via a network-facing port of the NVD and, afterperforming the necessary packet processing, may forward the packets andframes to a host machine via a host-facing port of the NVD.

In certain embodiments, there may be multiple ports and associated linksbetween an NVD and a TOR switch. These ports and links may be aggregatedto form a link aggregator group of multiple ports or links (referred toas a LAG). Link aggregation allows multiple physical links between twoend-points (e.g., between an NVD and a TOR switch) to be treated as asingle logical link. All the physical links in a given LAG may operatein full-duplex mode at the same speed. LAGs help increase the bandwidthand reliability of the connection between two endpoints. If one of thephysical links in the LAG goes down, traffic is dynamically andtransparently reassigned to one of the other physical links in the LAG.The aggregated physical links deliver higher bandwidth than eachindividual link. The multiple ports associated with a LAG are treated asa single logical port. Traffic can be load-balanced across the multiplephysical links of a LAG. One or more LAGs may be configured between twoendpoints. The two endpoints may be between an NVD and a TOR switch,between a host machine and an NVD, and the like.

An NVD implements or performs network virtualization functions. Thesefunctions are performed by software/firmware executed by the NVD.Examples of network virtualization functions include without limitation:packet encapsulation and de-capsulation functions; functions forcreating a VCN network; functions for implementing network policies suchas VCN security list (firewall) functionality; functions that facilitatethe routing and forwarding of packets to and from compute instances in aVCN; and the like. In certain embodiments, upon receiving a packet, anNVD is configured to execute a packet processing pipeline for processingthe packet and determining how the packet is to be forwarded or routed.As part of this packet processing pipeline, the NVD may execute one ormore virtual functions associated with the overlay network such asexecuting VNICs associated with cis in the VCN, executing a VirtualRouter (VR) associated with the VCN, the encapsulation and decapsulationof packets to facilitate forwarding or routing in the virtual network,execution of certain gateways (e.g., the Local Peering Gateway), theimplementation of Security Lists, Network Security Groups, networkaddress translation (NAT) functionality (e.g., the translation of PublicIP to Private IP on a host by host basis), throttling functions, andother functions.

In certain embodiments, the packet processing data path in an NVD maycomprise multiple packet pipelines, each composed of a series of packettransformation stages. In certain implementations, upon receiving apacket, the packet is parsed and classified to a single pipeline. Thepacket is then processed in a linear fashion, one stage after another,until the packet is either dropped or sent out over an interface of theNVD. These stages provide basic functional packet processing buildingblocks (e.g., validating headers, enforcing throttle, inserting newLayer-2 headers, enforcing L4 firewall, VCN encapsulation/decapsulation,etc.) so that new pipelines can be constructed by composing existingstages, and new functionality can be added by creating new stages andinserting them into existing pipelines.

An NVD may perform both control plane and data plane functionscorresponding to a control plane and a data plane of a VCN. Examples ofa VCN Control Plane are also depicted in FIGS. 12, 13, 14, and 15 (seereferences 1216, 1316, 1416, and 1516) and described below. Examples ofa VCN Data Plane are depicted in FIGS. 12, 13, 14, and 15 (seereferences 1218, 1318, 1418, and 1518) and described below. The controlplane functions include functions used for configuring a network (e.g.,setting up routes and route tables, configuring VNICs, etc.) thatcontrols how data is to be forwarded. In certain embodiments, a VCNControl Plane is provided that computes all the overlay-to-substratemappings centrally and publishes them to the NVDs and to the virtualnetwork edge devices such as various gateways such as the DRG, the SGW,the IGW, etc. Firewall rules may also be published using the samemechanism. In certain embodiments, an NVD only gets the mappings thatare relevant for that NVD. The data plane functions include functionsfor the actual routing/forwarding of a packet based upon configurationset up using control plane. A VCN data plane is implemented byencapsulating the customer’s network packets before they traverse thesubstrate network. The encapsulation/decapsulation functionality isimplemented on the NVDs. In certain embodiments, an NVD is configured tointercept all network packets in and out of host machines and performnetwork virtualization functions.

As indicated above, an NVD executes various virtualization functionsincluding VNICs and VCN VRs. An NVD may execute VNICs associated withthe compute instances hosted by one or more host machines connected tothe VNIC. For example, as depicted in FIG. 2 , NVD 210 executes thefunctionality for VNIC 276 that is associated with compute instance 268hosted by host machine 202 connected to NVD 210. As another example, NVD212 executes VNIC 280 that is associated with bare metal computeinstance 272 hosted by host machine 206, and executes VNIC 284 that isassociated with compute instance 274 hosted by host machine 208. A hostmachine may host compute instances belonging to different VCNs, whichbelong to different customers, and the NVD connected to the host machinemay execute the VNICs (i.e., execute VNICs-relate functionality)corresponding to the compute instances.

An NVD also executes VCN Virtual Routers corresponding to the VCNs ofthe compute instances. For example, in the embodiment depicted in FIG. 2, NVD 210 executes VCN VR 277 corresponding to the VCN to which computeinstance 268 belongs. NVD 212 executes one or more VCN VRs 283corresponding to one or more VCNs to which compute instances hosted byhost machines 206 and 208 belong. In certain embodiments, the VCN VRcorresponding to that VCN is executed by all the NVDs connected to hostmachines that host at least one compute instance belonging to that VCN.If a host machine hosts compute instances belonging to different VCNs,an NVD connected to that host machine may execute VCN VRs correspondingto those different VCNs.

In addition to VNICs and VCN VRs, an NVD may execute various software(e.g., daemons) and include one or more hardware components thatfacilitate the various network virtualization functions performed by theNVD. For purposes of simplicity, these various components are groupedtogether as “packet processing components” shown in FIG. 2 . Forexample, NVD 210 comprises packet processing components 286 and NVD 212comprises packet processing components 288. For example, the packetprocessing components for an NVD may include a packet processor that isconfigured to interact with the NVD’s ports and hardware interfaces tomonitor all packets received by and communicated using the NVD and storenetwork information. The network information may, for example, includenetwork flow information identifying different network flows handled bythe NVD and per flow information (e.g., per flow statistics). In certainembodiments, network flows information may be stored on a per VNICbasis. The packet processor may perform packet-by-packet manipulationsas well as implement stateful NAT and L4 firewall (FW). As anotherexample, the packet processing components may include a replicationagent that is configured to replicate information stored by the NVD toone or more different replication target stores. As yet another example,the packet processing components may include a logging agent that isconfigured to perform logging functions for the NVD. The packetprocessing components may also include software for monitoring theperformance and health of the NVD and, also possibly of monitoring thestate and health of other components connected to the NVD.

FIG. 1 shows the components of an example virtual or overlay networkincluding a VCN, subnets within the VCN, compute instances deployed onsubnets, VNICs associated with the compute instances, a VR for a VCN,and a set of gateways configured for the VCN. The overlay componentsdepicted in FIG. 1 may be executed or hosted by one or more of thephysical components depicted in FIG. 2 . For example, the computeinstances in a VCN may be executed or hosted by one or more hostmachines depicted in FIG. 2 . For a compute instance hosted by a hostmachine, the VNIC associated with that compute instance is typicallyexecuted by an NVD connected to that host machine (i.e., the VNICfunctionality is provided by the NVD connected to that host machine).The VCN VR function for a VCN is executed by all the NVDs that areconnected to host machines hosting or executing the compute instancesthat are part of that VCN. The gateways associated with a VCN may beexecuted by one or more different types of NVDs. For example, certaingateways may be executed by smartNICs, while others may be executed byone or more host machines or other implementations of NVDs.

As described above, a compute instance in a customer VCN may communicatewith various different endpoints, where the endpoints can be within thesame subnet as the source compute instance, in a different subnet butwithin the same VCN as the source compute instance, or with an endpointthat is outside the VCN of the source compute instance. Thesecommunications are facilitated using VNICs associated with the computeinstances, the VCN VRs, and the gateways associated with the VCNs.

For communications between two compute instances on the same subnet in aVCN, the communication is facilitated using VNICs associated with thesource and destination compute instances. The source and destinationcompute instances may be hosted by the same host machine or by differenthost machines. A packet originating from a source compute instance maybe forwarded from a host machine hosting the source compute instance toan NVD connected to that host machine. On the NVD, the packet isprocessed using a packet processing pipeline, which can includeexecution of the VNIC associated with the source compute instance. Sincethe destination endpoint for the packet is within the same subnet,execution of the VNIC associated with the source compute instanceresults in the packet being forwarded to an NVD executing the VNICassociated with the destination compute instance, which then processesand forwards the packet to the destination compute instance. The VNICsassociated with the source and destination compute instances may beexecuted on the same NVD (e.g., when both the source and destinationcompute instances are hosted by the same host machine) or on differentNVDs (e.g., when the source and destination compute instances are hostedby different host machines connected to different NVDs). The VNICs mayuse routing/forwarding tables stored by the NVD to determine the nexthop for the packet.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the packetoriginating from the source compute instance is communicated from thehost machine hosting the source compute instance to the NVD connected tothat host machine. On the NVD, the packet is processed using a packetprocessing pipeline, which can include execution of one or more VNICs,and the VR associated with the VCN. For example, as part of the packetprocessing pipeline, the NVD executes or invokes functionalitycorresponding to the VNIC (also referred to as executes the VNIC)associated with source compute instance. The functionality performed bythe VNIC may include looking at the VLAN tag on the packet. Since thepacket’s destination is outside the subnet, the VCN VR functionality isnext invoked and executed by the NVD. The VCN VR then routes the packetto the NVD executing the VNIC associated with the destination computeinstance. The VNIC associated with the destination compute instance thenprocesses the packet and forwards the packet to the destination computeinstance. The VNICs associated with the source and destination computeinstances may be executed on the same NVD (e.g., when both the sourceand destination compute instances are hosted by the same host machine)or on different NVDs (e.g., when the source and destination computeinstances are hosted by different host machines connected to differentNVDs).

If the destination for the packet is outside the VCN of the sourcecompute instance, then the packet originating from the source computeinstance is communicated from the host machine hosting the sourcecompute instance to the NVD connected to that host machine. The NVDexecutes the VNIC associated with the source compute instance. Since thedestination end point of the packet is outside the VCN, the packet isthen processed by the VCN VR for that VCN. The NVD invokes the VCN VRfunctionality, which may result in the packet being forwarded to an NVDexecuting the appropriate gateway associated with the VCN. For example,if the destination is an endpoint within the customer’s on-premisenetwork, then the packet may be forwarded by the VCN VR to the NVDexecuting the DRG gateway configured for the VCN. The VCN VR may beexecuted on the same NVD as the NVD executing the VNIC associated withthe source compute instance or by a different NVD. The gateway may beexecuted by an NVD, which may be a smartNIC, a host machine, or otherNVD implementation. The packet is then processed by the gateway andforwarded to a next hop that facilitates communication of the packet toits intended destination endpoint. For example, in the embodimentdepicted in FIG. 2 , a packet originating from compute instance 268 maybe communicated from host machine 202 to NVD 210 over link 220 (usingNIC 232). On NVD 210, VNIC 276 is invoked since it is the VNICassociated with source compute instance 268. VNIC 276 is configured toexamine the encapsulated information in the packet, and determine a nexthop for forwarding the packet with the goal of facilitatingcommunication of the packet to its intended destination endpoint, andthen forward the packet to the determined next hop.

A compute instance deployed on a VCN can communicate with variousdifferent endpoints. These endpoints may include endpoints that arehosted by CSPI 200 and endpoints outside CSPI 200. Endpoints hosted byCSPI 200 may include instances in the same VCN or other VCNs, which maybe the customer’s VCNs, or VCNs not belonging to the customer.Communications between endpoints hosted by CSPI 200 may be performedover physical network 218. A compute instance may also communicate withendpoints that are not hosted by CSPI 200, or are outside CSPI 200.Examples of these endpoints include endpoints within a customer’son-premise network or data center, or public endpoints accessible over apublic network such as the Internet. Communications with endpointsoutside CSPI 200 may be performed over public networks (e.g., theInternet) (not shown in FIG. 2 ) or private networks (not shown in FIG.2 ) using various communication protocols.

The architecture of CSPI 200 depicted in FIG. 2 is merely an example andis not intended to be limiting. Variations, alternatives, andmodifications are possible in alternative embodiments. For example, insome implementations, CSPI 200 may have more or fewer systems orcomponents than those shown in FIG. 2 , may combine two or more systems,or may have a different configuration or arrangement of systems. Thesystems, subsystems, and other components depicted in FIG. 2 may beimplemented in software (e.g., code, instructions, program) executed byone or more processing units (e.g., processors, cores) of the respectivesystems, using hardware, or combinations thereof. The software may bestored on a non-transitory storage medium (e.g., on a memory device).

FIG. 4 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy according tocertain embodiments. As depicted in FIG. 4 , host machine 402 executes ahypervisor 404 that provides a virtualized environment. Host machine 402executes two virtual machine instances, VM1 406 belonging tocustomer/tenant #1 and VM2 408 belonging to customer/tenant #2. Hostmachine 402 comprises a physical NIC 410 that is connected to an NVD 412via link 414. Each of the compute instances is attached to a VNIC thatis executed by NVD 412. In the embodiment in FIG. 4 , VM1 406 isattached to VNIC-VM1 420 and VM2 408 is attached to VNIC-VM2 422.

As shown in FIG. 4 , NIC 410 comprises two logical NICs, logical NIC A416 and logical NIC B 418. Each virtual machine is attached to andconfigured to work with its own logical NIC. For example, VM1 406 isattached to logical NIC A 416 and VM2 408 is attached to logical NIC B418. Even though host machine 402 comprises only one physical NIC 410that is shared by the multiple tenants, due to the logical NICs, eachtenant’s virtual machine believes they have their own host machine andNIC.

In certain embodiments, each logical NIC is assigned its own VLAN ID.Thus, a specific VLAN ID is assigned to logical NIC A 416 for Tenant #1and a separate VLAN ID is assigned to logical NIC B 418 for Tenant #2.When a packet is communicated from VM1 406, a tag assigned to Tenant #1is attached to the packet by the hypervisor and the packet is thencommunicated from host machine 402 to NVD 412 over link 414. In asimilar manner, when a packet is communicated from VM2 408, a tagassigned to Tenant #2 is attached to the packet by the hypervisor andthe packet is then communicated from host machine 402 to NVD 412 overlink 414. Accordingly, a packet 424 communicated from host machine 402to NVD 412 has an associated tag 426 that identifies a specific tenantand associated VM. On the NVD, for a packet 424 received from hostmachine 402, the tag 426 associated with the packet is used to determinewhether the packet is to be processed by VNIC-VM1 420 or by VNIC-VM2422. The packet is then processed by the corresponding VNIC. Theconfiguration depicted in FIG. 4 enables each tenant’s compute instanceto believe that they own their own host machine and NIC. The setupdepicted in FIG. 4 provides for I/O virtualization for supportingmulti-tenancy.

FIG. 5 depicts a simplified block diagram of a physical network 500according to certain embodiments. The embodiment depicted in FIG. 5 isstructured as a Clos network. A Clos network is a particular type ofnetwork topology designed to provide connection redundancy whilemaintaining high bisection bandwidth and maximum resource utilization. AClos network is a type of non-blocking, multistage or multi-tieredswitching network, where the number of stages or tiers can be two,three, four, five, etc. The embodiment depicted in FIG. 5 is a 3-tierednetwork comprising tiers 1, 2, and 3. The TOR switches 504 representTier-0 switches in the Clos network. One or more NVDs are connected tothe TOR switches. Tier-0 switches are also referred to as edge devicesof the physical network. The Tier-0 switches are connected to Tier-1switches, which are also referred to as leaf switches. In the embodimentdepicted in FIG. 5 , a set of “n” Tier-0 TOR switches are connected to aset of “n” Tier-1 switches and together form a pod. Each Tier-0 switchin a pod is interconnected to all the Tier-1 switches in the pod, butthere is no connectivity of switches between pods. In certainimplementations, two pods are referred to as a block. Each block isserved by or connected to a set of “n” Tier-2 switches (sometimesreferred to as spine switches). There can be several blocks in thephysical network topology. The Tier-2 switches are in turn connected to“n” Tier-3 switches (sometimes referred to as super-spine switches).Communication of packets over physical network 500 is typicallyperformed using one or more Layer-3 communication protocols. Typically,all the layers of the physical network, except for the TORs layer aren-ways redundant thus allowing for high availability. Policies may bespecified for pods and blocks to control the visibility of switches toeach other in the physical network so as to enable scaling of thephysical network.

A feature of a Clos network is that the maximum hop count to reach fromone Tier-0 switch to another Tier-0 switch (or from an NVD connected toa Tier-0- switch to another NVD connected to a Tier-0 switch) is fixed.For example, in a 3-Tiered Clos network at most seven hops are neededfor a packet to reach from one NVD to another NVD, where the source andtarget NVDs are connected to the leaf tier of the Clos network.Likewise, in a 4-tiered Clos network, at most nine hops are needed for apacket to reach from one NVD to another NVD, where the source and targetNVDs are connected to the leaf tier of the Clos network. Thus, a Closnetwork architecture maintains consistent latency throughout thenetwork, which is important for communication within and between datacenters. A Clos topology scales horizontally and is cost effective. Thebandwidth/throughput capacity of the network can be easily increased byadding more switches at the various tiers (e.g., more leaf and spineswitches) and by increasing the number of links between the switches atadjacent tiers.

In certain embodiments, each resource within CSPI is assigned a uniqueidentifier called a Cloud Identifier (CID). This identifier is includedas part of the resource’s information and can be used to manage theresource, for example, via a Console or through APIs. An example syntaxfor a CID is:

  ocid1.<RESOURCE TYPE>.<REALM>.[REGION][.FUTURE USE].<UNIQUE ID>

where,

-   ocid1: The literal string indicating the version of the CID;-   resource type: The type of resource (for example, instance, volume,    VCN, subnet, user, group, and so on);-   realm: The realm the resource is in. Example values are “c1” for the    commercial realm, “c2” for the Government Cloud realm, or “c3” for    the Federal Government Cloud realm, etc. Each realm may have its own    domain name;-   region: The region the resource is in. If the region is not    applicable to the resource, this part might be blank;-   future use: Reserved for future use.-   unique ID: The unique portion of the ID. The format may vary    depending on the type of resource or service.

FIG. 6 depicts a block diagram of a cloud infrastructure 600incorporating a CLOS network arrangement, according to certainembodiments. The cloud infrastructure 600 includes a plurality of racks(e.g., rack 1 610, and rack 2, 620). Each rack includes a plurality ofhost machines (also referred to herein as hosts). Rack 1 610 is depictedas including two host machines, i.e., host 1-A 612 and host 1-B 614, andrack 2 620 is depicted as including two host machines, i.e., host 2-A622 and host 2-B 624. It is appreciated that the illustration in FIG. 6(i.e., each rack including two host machines) is intended to beillustrative and non-limiting. For instance, the cloud infratsructuremay include more than two racks, where each rack may include more thantwo host machines. Moreover, it is noted that each rack is notrestricted to having the same number of hosts. Rather, a rack may have ahigher or lower number of host machines as compared to the number ofhost machines included in another rack.

Each host machine includes a plurality of graphical processing units(GPUs). For instance, host machine 1-A 612 includes N GPUs e.g., GPU 1,613. Moreover, it is appreciated that the illustration in FIG. 6 ofhaving each host machine including the same number of GPUs, i.e., NGPUs, is intended to be illustrative and non-limiting, i.e., each hostmachine can include a different number of GPUs. Each rack includes a topof rack (TOR) switch that is communicatively coupled with the GPUshosted on the host machines within the rack. For example, rack 1 610includes a TOR switch (i.e., TOR 1) 616 that is communicatively coupledto host machines Host 1-A, 612 and host 1-B, 614, whereas rack 2 620includes a TOR switch (i.e., TOR 2) 626 that is communicatively coupledto host machines Host 2-A, 622 and host 2-K, 624. It is appreciated thatthe TOR switches depicted in FIG. 6 (i.e., TOR 1 616, and TOR M 626),each include N ports that are used to communicatively couple the TORswitch to the N GPUs hosted on each host machine included in the rack.The coupling of TOR switches to the GPUs as depicted in FIG. 6 isintended to be illustrative and non-limiting. For instance, in someembodiments, the TOR switch may have a plurality of ports, each of whichcorresponds to a GPU on each host machine, i.e., a GPU on a host machinemay be connected to a unique port of the TOR via a communication link.

The TOR switches from each rack are communicatively coupled to aplurality of spine switches e.g., spine switch 1, 630 and spine switch P640. For example, as shown in FIG. 6 , TOR 1, 616 is connected to spineswitch 1 630 via two links, and to spine switch P 640 via another twolinks, respectively. Information transmitted from a particular TORswitch to a spine switch is referred to herein as communicationconducted via uplinks, whereas information transmitted from a spineswitch to a TOR switch is referred to herein as communication conductedvia downlinks. According to some embodiments, the TOR switches and thespine switches are connected in a CLOS network arrangement (e.g., amulti-stage switching network), where each TOR switch forms a ‘leaf’node in the CLOS network.

According to some embodiments, the GPUs included in the host machinesexecute tasks related to machine learning. In such a setting, a singletask may be performed/spread across a large number of GPUs (e.g., 64GPUs) that could be spread across multiple host machines and acrossmultiple racks. Since all these GPUs are working on the same task (i.e.,a workload), they all need to communicate with each other in a timesynchronized manner. Furthermore, at any given time, the GPUs are eitherin one of a compute mode or a communication mode, i.e., GPUs talk to oneanother at roughly the same time. The speed of the workload isdetermined by the speed of the slowest GPU.

Typically, to route packets from a source GPU to a destination GPU,equal cost multipath (ECMP) routing is utilized. In ECMP routing, whenthere are multiple equal cost paths available for routing traffic from asender to a receiver, a selection technique is used to select aparticular path. Accordingly, at a network device (e.g., a TOR switch ora spine switch) receiving the traffic, a selection algorithm is used toselect an outgoing link to be used for forwarding the traffic from thenetwork device to a subsequent device. This outgoing link selectionoccurs at each network device in the path from the sender to thereceiver. Hash-based selection is a widely used ECMP selectiontechnique, where the hash may be based, for example, on a 4-tuple of apacket (e.g., source port, destination port, source IP, destination IP).

ECMP routing is a flow aware routing technique, where each flow (i.e., astream of data packets) is hashed to the same path for the duration ofthe flow. Thus, packets in a flow are forwarded from a network deviceusing a particular outgoing port/link. This is typically done in orderto ensure that packets in a flow arrive in order, i.e., no re-orderingof packets is required. However, ECMP routing is bandwidth (orthroughput) unaware. In other words, the TOR and spine switches performstatistical flow-aware (throughput unaware) ECMP load balancing of flowson parallel links.

In standard ECMP routing (i.e., only flow aware routing), a problem isthat flows received by a network device over two separate incoming linksmay get hashed to the same outgoing link, thereby resulting in a flowcollision. For instance, consider a situation where the two flows arecoming in over two separate incoming 100G links, and each of the flowsgets hashed to the same 100G outgoing link. Such a situation results ina congestion (i.e., flow collision) and results in packets beingdropped, since the incoming bandwidth is 200G, but outgoing bandwidth is100G. As shown in FIG. 6 , there are two flows: flow 1 641 which isdirected from a first GPU of the host machine host 1-A, 612 to the TORswitch 616, and flow 2 643, which is directed from another GPU on thehost machine 614 to the TOR switch 616. Note that the two flows aredirected to the TOR switch on separate links. It is assumed that alllinks depicted in FIG. 6 have a capacity (i.e., bandwidth) of 100G. Inthe case when the TOR switch 616 performs ECMP routing algorithm, it ispossible that the two flows get hashed to use the same outgoing link ofthe TOR e.g., link 650 connecting the TOR switch 616 to spine switch630. In this case, there is a collision between the two flows(represented by ‘X’ mark), which results in packets being dropped.

Such a collision scenario is generally problematic for all types oftraffic irrespective of the protocol. For example, TCP is intelligent inthat when a packet gets dropped and the sender does not get anacknowledgment for that dropped packet, the packet is re-transmitted.However, the situation is worsened for remote direct memory access(RDMA) type traffic. RDMA networks do not use TCP for a variety ofreasons (e.g., TCP has complex logic that does not lend well to lowlatency and high performance). RDMA networks use protocols, such as RDMAover Infiniband or RDMA over converged Ethernet (RoCE). In RoCE, thereis a congestion control algorithm, wherein when a sender identifies theoccurrence of a congestion or dropped packets, the sender slows down thetransmission of packets. For a dropped packet, not only the droppedpackets, but also several packets around the dropped packet areretransmitted, which further eats away the available bandwidth andresults in poor performance.

The flow collision issue is a critical problem for workload executione.g., GPU workloads, due to the stringent time synchronizationrequirements. For example, GPUs may execute a machine learning task(i.e., a workload) where all GPUs need to communicate with each other ina time synchronized manner. Further, customer workloads can be ofdifferent types, each of which may have different requirements. Forinstance, a first workload (e.g., GPU workload) may be bandwidthsensitive, whereas a second workload (e.g., high performance compute(HPC) workload) may be delay or latency sensitive. Additionally,customers may desire to choose host machines to execute theirworkload(s) based on the application. For instance, for a delay (orlatency) sensitive workload, the customer may desire to choose hostmachines that are in close physical proximity of one another (e.g.,included in the same rack). In another example, the customer may desireto place their workloads in anti-affinity groups, i.e., spread the hostmachines across different racks to achieve higher availability in theoccurrence of faults in the network. Typically, host machines areallocated to customers (to execute their respective workloads) in anarbitrary (random) manner. As such, the likelihood for trafficcongestion is increased, which results in poor throughput of theworkload(s). Moreover, there is no mechanism available currently thatprovides customers with locality information of the host machines.

Described below are techniques to overcome the above-described problems.Specifically, the techniques described herein provide a hierarchy oflocality information of host machines to the customers, so that thecustomers may select specific host machines (based on the providedlocality information) to execute their workloads. For example, someembodiments of the present disclosure provide for customers to reducetheir application-to-service latency by “placing” their workload(s) onnearby host machines. Further, customers may use the localityinformation and place their workloads in ways to get higheranti-affinity and thus gain higher resiliency by reducing shared fate ofthe resources.

Turning now to FIG. 7 , there is illustrated an exemplary configurationof a rack 700, according to certain embodiments. As shown in FIG. 7 ,the rack 700 includes two host machines, i.e., host 1-A 710 and host 1-B720. It is appreciated that although rack 700 is depicted as includingtwo host machines, the rack 700 may include more host machines. Eachhost machine may further include a plurality of GPUs and a plurality ofCPUs.

The host machines (i.e., host 1-A 710 and host 1-B 720) arecommunicatively coupled to a network fabric via a top of rack switch,i.e., TOR 1 750. This network fabric is also referred to herein as afront-end network of the rack 700 and may correspond to an externalnetwork. The host machine, i.e., host 1-A 710 is connected to thefront-end network via a network interface card (NIC) 730 and a NVD 735(i.e., a network virtualization device), which is coupled to the TOR 1750. The host machine, i.e., host 1-B 720 is connected to the front-endnetwork via a network interface card (NIC) 740 and a NetworkVirtualization Device 745, which is coupled to the TOR 1 750. The hostmachines host 1-A 710 and host 1-B 720 are connected to a QoS-enabledback-end network on the other side. The QoS enabled backend network maycorrespond to a GPU cluster network as shown in FIG. 6 . Host machine1-A 710 is connected via another NIC 765 to a TOR 2 switch 760 whichcommunicatively couples the host machine to the back-end network.Similarly, host machine 1-B 720 is connected via NIC 780 to the TOR 2switch 760, which communicatively couples the host machine to theback-end network.

According to some embodiments, host machines are unaware of the physicaltopology of the network, i.e., a particular host machine is unaware ofthe physical location/position of other host machines in the network.For example, referring to FIG. 6 , host machine 1-A 612 is unaware thathost machine 1-B 614 is in fact included in the same rack (i.e., rack 1610) and positioned behind the same TOR switch, i.e., TOR 1 616.However, a network control plane is aware of the overall physicaltopology of the host machines. In one implementation, the networkcontrol plane publishes such locality information to the host machinesin order to achieve traffic locality and avoid needless trafficcongestion. Doing so has a significant impact on the performance ofworkloads.

By some embodiments, the network control plane utilizes an instancemetadata service (IMDS) to publish (and store) metadata information(e.g., locality information) to a host machine. Such metadatainformation may be published to the host machine(s) via the respectiveNVDs associated with the host machine(s). For example, referring to FIG.7 , locality information is published (via IMDS) to host 1-A 710 via NVD735, whereas locality information is published (via IMDS) to host 1-B720 via NVD 745. It is appreciated that locality information may includemetadata indicating a hierarchy of locality information of the hostmachine as described next with reference to FIG. 8 and FIG. 10 . It isappreciated that each of the host machines may query the IMDS to obtainthe metadata information associated with the host machine.

FIG. 8 depicts a schematic illustrating a hierarchy of localityinformation 850 of a host machine, according to certain embodiments. Forsake of illustration, each rack in FIG. 8 is depicted to include twohost machines. For instance, rack 1 801 includes two host machines H1and H2 (associated with TOR switch, i.e., TOR 1), rack 2 803 includestwo host machines H3 and H4 (associated with TOR switch, i.e., TOR 2),rack 3 811 includes two host machines H5 and H6 (associated with TORswitch, i.e., TOR 3), and rack 4 813 includes two host machines H7 andH8 (associated with TOR switch, i.e., TOR 4). In a similar manner, rack5 821-rack 8 833 are depicted to include two host machines respectively.It is appreciated that each rack is in no way limited to include twohost machines. Rather, each rack may include a greater number of hostmachines, and moreover the number of host machines included in a rackmay be different as compared to the number of host machines included inanother rack.

According to some embodiments, a collection of racks may constitute ablock. For instance, rack 1 (801) and rack 2 (803) constitute block 1805, whereas rack 3 (811) and rack 4 (813) constitute block 2 (815). Ina similar manner, rack 5 (821) and rack 6 (823) constitute block 3(825), and rack 7 (831) and rack 8 (833) constitute block 4 (835).Further, a collection of blocks may constitute a building. For instance,block 1 805 and block 2 815 may constitute a building 1 820, whereasblock 3 825 and block 4 835 may constitute building 2 840. A collectionof buildings may constitute an availability domain. For example, asshown in FIG. 8 , building 1 820 and building 2 840 may be included inavailability domain 1 850.

It is appreciated that host machines included in the same rack e.g., H1and H2 included in rack 1 801, share a top of rack (i.e., TOR) switchassociated with the rack. Further, blocks correspond to racks that arepositioned nearby (i.e., in close geographical proximity) one anothere.g., rack 1 801 and rack 2 803 that are included in block 1 805 arepositioned proximate to each other, as opposed to racks that arepositioned further away from one another e.g., rack 1 801 (included inblock 1 805) and rack 4 (included in block 2). Moreover, a collection ofbuildings may correspond to an availability domain (e.g., datacenter),i.e., building 1 820 and building 2 840 that are included inavailability domain 1 850. Thus, as described below with reference toFIG. 9 , the locality information of a host machine has multiple levelsof hierarchical information such as: rack location, block location,building location, and availability domain location.

FIG. 9 illustrates an exemplary tree diagram illustrating levels (i.e.,a hierarchy) of locality information of a host machine, according tocertain embodiments. The hierarchical locality information is depictedin decreasing order of latency. As shown in FIG. 9 , level 1 of thehierarchical locality information includes a plurality of availabilitydomains (AD) e.g., AD 1, AD 2 ... AD K. At level 2, each availabilitydomain may include a plurality of buildings e.g., building 1, building 2....building L that are included in availability domain 2. At level 3,each building may include a plurality of blocks e.g., block 1, block 2....block M that are included in building 2. Finally, at level 4 (i.e.,the level with the minimum amount of latency), each block may includeone or more racks, each of which includes one or more host machines. Forexample, as shown in FIG. 9 , block 2 includes a plurality of racks,i.e., rack 1, rack 2...rack N. Hierarchical locality information for aparticular host located in rack 2 comprises the information, in thelocality tree depicted in FIG. 9 , that identifies the nodes between theroot node and the host location (e.g., for Host A, hierarchical localityinformation comprises Availability _domain_2 ➔ Building_2 ➔ Block_2 ➔Rack_2).

According to some embodiments, each host machine can communicate withthe instance metadata service (IMDS) to obtain hierarchical localityinformation related to the host machine. For instance, each host machineis associated with a NVD that can have an application being executedtherein to communicate with a private IP address (e.g., address of theIMDS) to obtain hierarchical locality information. In oneimplementation, the host machine can obtain an encoded array ofhierarchical locality information from the IMDS. Further, as will bedescribed below with reference to FIG. 10 , the encoded hierarchicallocality information can be unique to a customer.

FIG. 10 illustrates an exemplary encoded array of hierarchical localityinformation of a host machine, according to certain embodiments. Theencoded array of hierarchical locality information 1000 includes aplurality of blocks of hashed information e.g., hash block 1 1010, hashblock 2 1020, hash block 3 1030, and hash block 4 1040. It isappreciated that two sequential hash blocks may be separated by anidentifier 1015 that may correspond to a hyphen, semicolon, comma, orthe like.

In one implementation, hash block 1 1010 may include a hash of a rackidentifier (i.e., an ID of a rack that includes the host machine) and atenant ID, i.e., customer ID. In doing so, the encoded array is uniqueper customer. Specifically, by including customer information (e.g.,tenant ID) in the hash blocks prevents two customers that happen to havehost machines on the same rack from realizing that they are on the samerack. However, it enables a particular customer to know instances of thecustomer that are being executed on the same rack. In other words, theencoded array provides hierarchical locality information for aparticular customer without revealing the placement(s) of othercustomers. In a similar manner, hash block 1020 may include a hash of ablock identifier and the tenant ID, whereas hash block 1030 may includea hash of a building identifier and the tenant ID, and hash block 1040may include a hash of an availability domain identifier and the tenantID.

By some embodiments, the hierarchical locality information of hostmachines may be provided to customers of the cloud infrastructure. Indoing so, the customers can utilize the hierarchical localityinformation of the host machines to provision workloads based on thetype of application associated with the workload. For instance, for aworkload which demands low latency, a user may utilize informationincluded in hash block 1 (1010), i.e., rack information, to select hostmachines on the same rack or adjacent racks. As another example, for GPUworkloads, locality information may be used to configure bandwidthefficient communication patterns e.g., move large amounts of data in aquick manner. With regard to applications that require high availabilityor applications executed on the front-end network side of the rack (seeFIG. 7 ), the user may utilize information included in one or more ofthe hash blocks (i.e., hash blocks 1010, 1020, 1030, and/or 1040 of FIG.10 ) to select, for instance, host machines that belong different racks,or blocks, or buildings to attain a certain level of anti-affinity(i.e., high availability). It is appreciated that the hierarchicallocality information of host machines may be utilized by applications,such as distributed Hadoop workloads and/or high frequency tradingapplications (that require selection of one or more host machines tosupport the application), in the selection of one or more host machinesto execute the desired task(s).

As another example, considering a file-system case, the network localityinformation may be utilized to place a client in close proximity of afile system server to achieve low latency. Yet another application is adatabase application that comprises of three tiers, i.e., a client tier,a middle-tier (e.g., an application server tier), and a database tier.In such an application, a customer may desire low latency for a databaseworkload. The customer may utilize the network locality information toappropriately place the client, the middle-tier server, and the databaseto achieve low latency. It is appreciated that in this scenario, thecustomer may simultaneously achieve high availability in the middle tierand the database tier by utilizing the network locality information.

FIG. 11A illustrates an exemplary flowchart depicting steps performed inprovisioning a request, according to certain embodiments. The processingdepicted in FIG. 11 may be implemented in software (e.g., code,instructions, program) executed by one or more processing units (e.g.,processors, cores) of the respective systems, hardware, or combinationsthereof. The software may be stored on a non-transitory storage medium(e.g., on a memory device). The method 1100 presented in FIG. 11 anddescribed below is intended to be illustrative and non-limiting.Although FIG. 11 depicts the various processing steps occurring in aparticular sequence or order, this is not intended to be limiting. Incertain alternative embodiments, the steps may be performed in somedifferent order or some steps may also be performed in parallel.

The process commences in step 1105, where for each host machine of aplurality of host machines (i.e., host machines included in a cluster)hierarchical locality information for the host machine is stored.Hierarchical locality information for a host machine includesinformation identifying, for each locality of a plurality of localities,location information for the locality. By some embodiments, the instancemetadata service may be utilized to store the hierarchical localityinformation in the host machine via the network virtualization device(NVD) associated with the host machine. As shown in FIG. 9 , it is notedthat hierarchical locality information may correspond to informationthat indicates an identifier of a rack (i.e., rack ID) which includesthe host machine, an identifier of a block which includes the rack, anidentifier of a building which includes the block, and an identifier ofa domain which includes the building.

In step 1110, a control plane receives a request (e.g., from a customer)requesting execution of a workload. Note that by one embodiment, aworkload corresponds to one or more processes that are to be executedusing the GPUs associated with the host machines. The process then movesto step 1115, where hierarchical locality information for each of theplurality of host machines is obtained. It is noted that thehierarchical locality information (of each host machine) may be storedby the instance metadata service in the corresponding host machine.

Thereafter, the process moves to step 1120, where the hierarchicallocality information of the plurality of host machines is provided inresponse to the request. According to some embodiments, the customerupon obtaining the hierarchical locality information of the plurality ofhost machines may select one or more host machines for executing aworkload. The selection of one or more host machines is based on one ormore constraints associated with the workload. Details pertaining to theconstraints are described later with reference to FIG. 11B. In step1125, the control plane receives the selection of the one or more hostmachines. In step 1130, the process proceeds to execute the workload onthe selected one or more host machines.

It is appreciated that the above described steps of utilizinghierarchical locality information of the host machines to execute aworkload is in no way limiting the scope of the present disclosure.Rather certain modifications to the steps are well within the scope ofthe present disclosure. For instance, in one embodiment and as describednext with reference to FIG. 11B, rather than the customer selecting thenumber of host machines for executing the workload, the control planemay select the number of host machines for the customer (i.e., based onthe one or more constraints associated with the workload of thecustomer).

FIG. 11B illustrates another exemplary flowchart depicting stepsperformed in provisioning a customer’s workload request, according tocertain embodiments. The processing depicted in FIG. 11 may beimplemented in software (e.g., code, instructions, program) executed byone or more processing units (e.g., processors, cores) of the respectivesystems, hardware, or combinations thereof. The software may be storedon a non-transitory storage medium (e.g., on a memory device). Themethod 1150 presented in FIG. 11 and described below is intended to beillustrative and non-limiting. Although FIG. 11 depicts the variousprocessing steps occurring in a particular sequence or order, this isnot intended to be limiting. In certain alternative embodiments, thesteps may be performed in some different order or some steps may also beperformed in parallel.

The process commences in step 1155, where for each host machine of aplurality of host machines (i.e., host machines included in a cluster)hierarchical locality information for the host machine is stored.Hierarchical locality information for a host machine includesinformation identifying, for each locality of a plurality of localities,location information for the locality. By some embodiments, the instancemetadata service may be utilized to store the hierarchical localityinformation in the host machine via the network virtualization device(NVD) associated with the host machine. As shown in FIG. 9 , it is notedthat hierarchical locality information may correspond to informationthat indicates an identifier of a rack (i.e., rack ID) which includesthe host machine, an identifier of a block which includes the rack, anidentifier of a building which includes the block, and an identifier ofa domain which includes the building.

In step 1160, a request is received from a customer. The requestrequests a number of host machines desired by the customer to execute aworkload. It is appreciated that request may include metadatacorresponding to one or more constraints associated with the workload.By some embodiments, the one or more constraints can include a firstconstraint associated with a latency threshold, i.e., the customer maydesire the workload to be executed by having the latency be lower than apredetermined threshold value. A second constraint may correspond to ananti-affinity constraint. Such a constraint corresponds to the customerdesiring to have a certain degree of availability of the host machines,i.e., at least some of the host machines selected for executing theworkload need to be positioned in different racks. Such a constraint istypically incorporated by the customer to address failure of rackissues.

In step 1165, the one or more constraints are extracted from the requestreceived in step 1160. Thereafter, the process moves to step 1170, wherethe control plane allocates one or more host machines (from theplurality of host machines) to execute the workload of the customer. Itis appreciated that the host machines allocated for executing theworkload may be determined in accordance with the one or moreconstraints identified in step 1115 and/or the hierarchical localityinformation of the host machines. According to some embodiments, theprocess in step 1170 allocates host machines to execute the workload inaccordance with the topology of the network cluster (e.g., number ofhost machines included in a rack, number of racks available in thesystem). Consider for example that each rack includes a total of N hostmachines, and that the number of host machines requested by the user isK host machines. In case K is less than N (i.e., K<N), then in oneimplementation all the K host machines may be allocated from a singlerack, i.e., all K host machines may be positioned behind a single TORswitch. It is noted that such an allocation will result in minimallatency. However, it is appreciated that such an allocation may beprovided pending user approval, as the user may also desire to achieve acertain level of anti-affinity, i.e., availability, in which case someof the host machines that are allocated to the user may be selected fromother rack(s) from the network cluster. Another example may correspondto the case of K being greater than N (K>N), i.e., the number of hostmachines requested by the user is greater than the number of hostmachines included in a rack. In this case, by one implementation, theallocation may be performed in a manner such that least number of TORswitches are used, i.e., intra-rack routing is minimized. Thereafter,the process moves to step 1175, where the hierarchical localityinformation of the allocated host machines is provided to the customer.The process moves to step 1180, where the customer’s workload isexecuted on the allocated one or more host machines for the customer.

Example Cloud Infrastructure Embodiment

As noted above, infrastructure as a service (IaaS) is one particulartype of cloud computing. IaaS can be configured to provide virtualizedcomputing resources over a public network (e.g., the Internet). In anIaaS model, a cloud computing provider can host the infrastructurecomponents (e.g., servers, storage devices, network nodes (e.g.,hardware), deployment software, platform virtualization (e.g., ahypervisor layer), or the like). In some cases, an IaaS provider mayalso supply a variety of services to accompany those infrastructurecomponents (e.g., billing, monitoring, logging, security, load balancingand clustering, etc.). Thus, as these services may be policy-driven,IaaS users may be able to implement policies to drive load balancing tomaintain application availability and performance.

In some instances, IaaS customers may access resources and servicesthrough a wide area network (WAN), such as the Internet, and can use thecloud provider’s services to install the remaining elements of anapplication stack. For example, the user can log in to the IaaS platformto create virtual machines (VMs), install operating systems (OSs) oneach VM, deploy middleware such as databases, create storage buckets forworkloads and backups, and even install enterprise software into thatVM. Customers can then use the provider’s services to perform variousfunctions, including balancing network traffic, troubleshootingapplication issues, monitoring performance, managing disaster recovery,etc.

In most cases, a cloud computing model will require the participation ofa cloud provider. The cloud provider may, but need not be, a third-partyservice that specializes in providing (e.g., offering, renting, selling)IaaS. An entity might also opt to deploy a private cloud, becoming itsown provider of infrastructure services.

In some examples, IaaS deployment is the process of putting a newapplication, or a new version of an application, onto a preparedapplication server or the like. It may also include the process ofpreparing the server (e.g., installing libraries, daemons, etc.). Thisis often managed by the cloud provider, below the hypervisor layer(e.g., the servers, storage, network hardware, and virtualization).Thus, the customer may be responsible for handling (OS), middleware,and/or application deployment (e.g., on self-service virtual machines(e.g., that can be spun up on demand) or the like.

In some examples, IaaS provisioning may refer to acquiring computers orvirtual hosts for use, and even installing needed libraries or serviceson them. In most cases, deployment does not include provisioning, andthe provisioning may need to be performed first.

In some cases, there are two different challenges for IaaS provisioning.First, there is the initial challenge of provisioning the initial set ofinfrastructure before anything is running. Second, there is thechallenge of evolving the existing infrastructure (e.g., adding newservices, changing services, removing services, etc.) once everythinghas been provisioned. In some cases, these two challenges may beaddressed by enabling the configuration of the infrastructure to bedefined declaratively. In other words, the infrastructure (e.g., whatcomponents are needed and how they interact) can be defined by one ormore configuration files. Thus, the overall topology of theinfrastructure (e.g., what resources depend on which, and how they eachwork together) can be described declaratively. In some instances, oncethe topology is defined, a workflow can be generated that creates and/ormanages the different components described in the configuration files.

In some examples, an infrastructure may have many interconnectedelements. For example, there may be one or more virtual private clouds(VPCs) (e.g., a potentially on-demand pool of configurable and/or sharedcomputing resources), also known as a core network. In some examples,there may also be one or more security group rules provisioned to definehow the security of the network will be set up and one or more virtualmachines (VMs). Other infrastructure elements may also be provisioned,such as a load balancer, a database, or the like. As more and moreinfrastructure elements are desired and/or added, the infrastructure mayincrementally evolve.

In some instances, continuous deployment techniques may be employed toenable deployment of infrastructure code across various virtualcomputing environments. Additionally, the described techniques canenable infrastructure management within these environments. In someexamples, service teams can write code that is desired to be deployed toone or more, but often many, different production environments (e.g.,across various different geographic locations, sometimes spanning theentire world). However, in some examples, the infrastructure on whichthe code will be deployed must first be set up. In some instances, theprovisioning can be done manually, a provisioning tool may be utilizedto provision the resources, and/or deployment tools may be utilized todeploy the code once the infrastructure is provisioned.

FIG. 12 is a block diagram 1200 illustrating an example pattern of anIaaS architecture, according to at least one embodiment. Serviceoperators 1202 can be communicatively coupled to a secure host tenancy1204 that can include a virtual cloud network (VCN) 1206 and a securehost subnet 1208. In some examples, the service operators 1202 may beusing one or more client computing devices, which may be portablehandheld devices (e.g., an iPhone®, cellular telephone, an iPad®,computing tablet, a personal digital assistant (PDA)) or wearabledevices (e.g., a Google Glass® head mounted display), running softwaresuch as Microsoft Windows Mobile®, and/or a variety of mobile operatingsystems such as iOS, Windows Phone, Android, BlackBerry 8, Palm OS, andthe like, and being Internet, e-mail, short message service (SMS),Blackberry®, or other communication protocol enabled. Alternatively, theclient computing devices can be general purpose personal computersincluding, by way of example, personal computers and/or laptop computersrunning various versions of Microsoft Windows®, Apple Macintosh®, and/orLinux operating systems. The client computing devices can be workstationcomputers running any of a variety of commercially-available UNIX® orUNIX-like operating systems, including without limitation the variety ofGNU/Linux operating systems, such as for example, Google Chrome OS.Alternatively, or in addition, client computing devices may be any otherelectronic device, such as a thin-client computer, an Internet-enabledgaming system (e.g., a Microsoft Xbox gaming console with or without aKinect® gesture input device), and/or a personal messaging device,capable of communicating over a network that can access the VCN 1206and/or the Internet.

The VCN 1206 can include a local peering gateway (LPG) 1210 that can becommunicatively coupled to a secure shell (SSH) VCN 1212 via an LPG 1210contained in the SSH VCN 1212. The SSH VCN 1212 can include an SSHsubnet 1214, and the SSH VCN 1212 can be communicatively coupled to acontrol plane VCN 1216 via the LPG 1210 contained in the control planeVCN 1216. Also, the SSH VCN 1212 can be communicatively coupled to adata plane VCN 1218 via an LPG 1210. The control plane VCN 1216 and thedata plane VCN 1218 can be contained in a service tenancy 1219 that canbe owned and/or operated by the IaaS provider.

The control plane VCN 1216 can include a control plane demilitarizedzone (DMZ) tier 1220 that acts as a perimeter network (e.g., portions ofa corporate network between the corporate intranet and externalnetworks). The DMZ-based servers may have restricted responsibilitiesand help keep security breaches contained. Additionally, the DMZ tier1220 can include one or more load balancer (LB) subnet(s) 1222, acontrol plane app tier 1224 that can include app subnet(s) 1226, acontrol plane data tier 1228 that can include database (DB) subnet(s)1230 (e.g., frontend DB subnet(s) and/or backend DB subnet(s)). The LBsubnet(s) 1222 contained in the control plane DMZ tier 1220 can becommunicatively coupled to the app subnet(s) 1226 contained in thecontrol plane app tier 1224 and an Internet gateway 1234 that can becontained in the control plane VCN 1216, and the app subnet(s) 1226 canbe communicatively coupled to the DB subnet(s) 1230 contained in thecontrol plane data tier 1228 and a service gateway 1236 and a networkaddress translation (NAT) gateway 1238. The control plane VCN 1216 caninclude the service gateway 1236 and the NAT gateway 1238.

The control plane VCN 1216 can include a data plane mirror app tier 1240that can include app subnet(s) 1226. The app subnet(s) 1226 contained inthe data plane mirror app tier 1240 can include a virtual networkinterface controller (VNIC) 1242 that can execute a compute instance1244. The compute instance 1244 can communicatively couple the appsubnet(s) 1226 of the data plane mirror app tier 1240 to app subnet(s)1226 that can be contained in a data plane app tier 1246.

The data plane VCN 1218 can include the data plane app tier 1246, a dataplane DMZ tier 1248, and a data plane data tier 1250. The data plane DMZtier 1248 can include LB subnet(s) 1222 that can be communicativelycoupled to the app subnet(s) 1226 of the data plane app tier 1246 andthe Internet gateway 1234 of the data plane VCN 1218. The app subnet(s)1226 can be communicatively coupled to the service gateway 1236 of thedata plane VCN 1218 and the NAT gateway 1238 of the data plane VCN 1218.The data plane data tier 1250 can also include the DB subnet(s) 1230that can be communicatively coupled to the app subnet(s) 1226 of thedata plane app tier 1246.

The Internet gateway 1234 of the control plane VCN 1216 and of the dataplane VCN 1218 can be communicatively coupled to a metadata managementservice 1252 that can be communicatively coupled to public Internet1254. Public Internet 1254 can be communicatively coupled to the NATgateway 1238 of the control plane VCN 1216 and of the data plane VCN1218. The service gateway 1236 of the control plane VCN 1216 and of thedata plane VCN 1218 can be communicatively couple to cloud services1256.

In some examples, the service gateway 1236 of the control plane VCN 1216or of the data plane VCN 1218 can make application programming interface(API) calls to cloud services 1256 without going through public Internet1254. The API calls to cloud services 1256 from the service gateway 1236can be one-way: the service gateway 1236 can make API calls to cloudservices 1256, and cloud services 1256 can send requested data to theservice gateway 1236. But, cloud services 1256 may not initiate APIcalls to the service gateway 1236.

In some examples, the secure host tenancy 1204 can be directly connectedto the service tenancy 1219, which may be otherwise isolated. The securehost subnet 1208 can communicate with the SSH subnet 1214 through an LPG1210 that may enable two-way communication over an otherwise isolatedsystem. Connecting the secure host subnet 1208 to the SSH subnet 1214may give the secure host subnet 1208 access to other entities within theservice tenancy 1219.

The control plane VCN 1216 may allow users of the service tenancy 1219to set up or otherwise provision desired resources. Desired resourcesprovisioned in the control plane VCN 1216 may be deployed or otherwiseused in the data plane VCN 1218. In some examples, the control plane VCN1216 can be isolated from the data plane VCN 1218, and the data planemirror app tier 1240 of the control plane VCN 1216 can communicate withthe data plane app tier 1246 of the data plane VCN 1218 via VNICs 1242that can be contained in the data plane mirror app tier 1240 and thedata plane app tier 1246.

In some examples, users of the system, or customers, can make requests,for example create, read, update, or delete (CRUD) operations, throughpublic Internet 1254 that can communicate the requests to the metadatamanagement service 1252. The metadata management service 1252 cancommunicate the request to the control plane VCN 1216 through theInternet gateway 1234. The request can be received by the LB subnet(s)1222 contained in the control plane DMZ tier 1220. The LB subnet(s) 1222may determine that the request is valid, and in response to thisdetermination, the LB subnet(s) 1222 can transmit the request to appsubnet(s) 1226 contained in the control plane app tier 1224. If therequest is validated and requires a call to public Internet 1254, thecall to public Internet 1254 may be transmitted to the NAT gateway 1238that can make the call to public Internet 1254. Memory that may bedesired to be stored by the request can be stored in the DB subnet(s)1230.

In some examples, the data plane mirror app tier 1240 can facilitatedirect communication between the control plane VCN 1216 and the dataplane VCN 1218. For example, changes, updates, or other suitablemodifications to configuration may be desired to be applied to theresources contained in the data plane VCN 1218. Via a VNIC 1242, thecontrol plane VCN 1216 can directly communicate with, and can therebyexecute the changes, updates, or other suitable modifications toconfiguration to, resources contained in the data plane VCN 1218.

In some embodiments, the control plane VCN 1216 and the data plane VCN1218 can be contained in the service tenancy 1219. In this case, theuser, or the customer, of the system may not own or operate either thecontrol plane VCN 1216 or the data plane VCN 1218. Instead, the IaaSprovider may own or operate the control plane VCN 1216 and the dataplane VCN 1218, both of which may be contained in the service tenancy1219. This embodiment can enable isolation of networks that may preventusers or customers from interacting with other users’, or othercustomers’, resources. Also, this embodiment may allow users orcustomers of the system to store databases privately without needing torely on public Internet 1254, which may not have a desired level ofsecurity, for storage.

In other embodiments, the LB subnet(s) 1222 contained in the controlplane VCN 1216 can be configured to receive a signal from the servicegateway 1236. In this embodiment, the control plane VCN 1216 and thedata plane VCN 1218 may be configured to be called by a customer of theIaaS provider without calling public Internet 1254. Customers of theIaaS provider may desire this embodiment since database(s) that thecustomers use may be controlled by the IaaS provider and may be storedon the service tenancy 1219, which may be isolated from public Internet1254.

FIG. 13 is a block diagram 1300 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1302 (e.g. service operators 1202 of FIG. 12 ) can becommunicatively coupled to a secure host tenancy 1304 (e.g. the securehost tenancy 1204 of FIG. 12 ) that can include a virtual cloud network(VCN) 1306 (e.g. the VCN 1206 of FIG. 12 ) and a secure host subnet 1308(e.g. the secure host subnet 1208 of FIG. 12 ). The VCN 1306 can includea local peering gateway (LPG) 1310 (e.g. the LPG 1210 of FIG. 12 ) thatcan be communicatively coupled to a secure shell (SSH) VCN 1312 (e.g.the SSH VCN 1212 of FIG. 12 ) via an LPG 1310 contained in the SSH VCN1312. The SSH VCN 1312 can include an SSH subnet 1314 (e.g. the SSHsubnet 1214 of FIG. 12 ), and the SSH VCN 1312 can be communicativelycoupled to a control plane VCN 1316 (e.g. the control plane VCN 1216 ofFIG. 12 ) via an LPG 1310 contained in the control plane VCN 1316. Thecontrol plane VCN 1316 can be contained in a service tenancy 1319 (e.g.the service tenancy 1219 of FIG. 12 ), and the data plane VCN 1318 (e.g.the data plane VCN 1218 of FIG. 12 ) can be contained in a customertenancy 1321 that may be owned or operated by users, or customers, ofthe system.

The control plane VCN 1316 can include a control plane DMZ tier 1320(e.g. the control plane DMZ tier 1220 of FIG. 12 ) that can include LBsubnet(s) 1322 (e.g. LB subnet(s) 1222 of FIG. 12 ), a control plane apptier 1324 (e.g. the control plane app tier 1224 of FIG. 12 ) that caninclude app subnet(s) 1326 (e.g. app subnet(s) 1226 of FIG. 12 ), acontrol plane data tier 1328 (e.g. the control plane data tier 1228 ofFIG. 12 ) that can include database (DB) subnet(s) 1330 (e.g. similar toDB subnet(s) 1230 of FIG. 12 ). The LB subnet(s) 1322 contained in thecontrol plane DMZ tier 1320 can be communicatively coupled to the appsubnet(s) 1326 contained in the control plane app tier 1324 and anInternet gateway 1334 (e.g. the Internet gateway 1234 of FIG. 12 ) thatcan be contained in the control plane VCN 1316, and the app subnet(s)1326 can be communicatively coupled to the DB subnet(s) 1330 containedin the control plane data tier 1328 and a service gateway 1336 (e.g. theservice gateway of FIG. 12 ) and a network address translation (NAT)gateway 1338 (e.g. the NAT gateway 1238 of FIG. 12 ). The control planeVCN 1316 can include the service gateway 1336 and the NAT gateway 1338.

The control plane VCN 1316 can include a data plane mirror app tier 1340(e.g. the data plane mirror app tier 1240 of FIG. 12 ) that can includeapp subnet(s) 1326. The app subnet(s) 1326 contained in the data planemirror app tier 1340 can include a virtual network interface controller(VNIC) 1342 (e.g. the VNIC of 1242) that can execute a compute instance1344 (e.g. similar to the compute instance 1244 of FIG. 12 ). Thecompute instance 1344 can facilitate communication between the appsubnet(s) 1326 of the data plane mirror app tier 1340 and the appsubnet(s) 1326 that can be contained in a data plane app tier 1346 (e.g.the data plane app tier 1246 of FIG. 12 ) via the VNIC 1342 contained inthe data plane mirror app tier 1340 and the VNIC 1342 contained in thedata plane app tier 1346.

The Internet gateway 1334 contained in the control plane VCN 1316 can becommunicatively coupled to a metadata management service 1352 (e.g. themetadata management service 1252 of FIG. 12 ) that can becommunicatively coupled to public Internet 1354 (e.g. public Internet1254 of FIG. 12 ). Public Internet 1354 can be communicatively coupledto the NAT gateway 1338 contained in the control plane VCN 1316. Theservice gateway 1336 contained in the control plane VCN 1316 can becommunicatively couple to cloud services 1356 (e.g. cloud services 1256of FIG. 12 ).

In some examples, the data plane VCN 1318 can be contained in thecustomer tenancy 1321. In this case, the IaaS provider may provide thecontrol plane VCN 1316 for each customer, and the IaaS provider may, foreach customer, set up a unique compute instance 1344 that is containedin the service tenancy 1319. Each compute instance 1344 may allowcommunication between the control plane VCN 1316, contained in theservice tenancy 1319, and the data plane VCN 1318 that is contained inthe customer tenancy 1321. The compute instance 1344 may allowresources, that are provisioned in the control plane VCN 1316 that iscontained in the service tenancy 1319, to be deployed or otherwise usedin the data plane VCN 1318 that is contained in the customer tenancy1321.

In other examples, the customer of the IaaS provider may have databasesthat live in the customer tenancy 1321. In this example, the controlplane VCN 1316 can include the data plane mirror app tier 1340 that caninclude app subnet(s) 1326. The data plane mirror app tier 1340 canreside in the data plane VCN 1318, but the data plane mirror app tier1340 may not live in the data plane VCN 1318. That is, the data planemirror app tier 1340 may have access to the customer tenancy 1321, butthe data plane mirror app tier 1340 may not exist in the data plane VCN1318 or be owned or operated by the customer of the IaaS provider. Thedata plane mirror app tier 1340 may be configured to make calls to thedata plane VCN 1318 but may not be configured to make calls to anyentity contained in the control plane VCN 1316. The customer may desireto deploy or otherwise use resources in the data plane VCN 1318 that areprovisioned in the control plane VCN 1316, and the data plane mirror apptier 1340 can facilitate the desired deployment, or other usage ofresources, of the customer.

In some embodiments, the customer of the IaaS provider can apply filtersto the data plane VCN 1318. In this embodiment, the customer candetermine what the data plane VCN 1318 can access, and the customer mayrestrict access to public Internet 1354 from the data plane VCN 1318.The IaaS provider may not be able to apply filters or otherwise controlaccess of the data plane VCN 1318 to any outside networks or databases.Applying filters and controls by the customer onto the data plane VCN1318, contained in the customer tenancy 1321, can help isolate the dataplane VCN 1318 from other customers and from public Internet 1354.

In some embodiments, cloud services 1356 can be called by the servicegateway 1336 to access services that may not exist on public Internet1354, on the control plane VCN 1316, or on the data plane VCN 1318. Theconnection between cloud services 1356 and the control plane VCN 1316 orthe data plane VCN 1318 may not be live or continuous. Cloud services1356 may exist on a different network owned or operated by the IaaSprovider. Cloud services 1356 may be configured to receive calls fromthe service gateway 1336 and may be configured to not receive calls frompublic Internet 1354. Some cloud services 1356 may be isolated fromother cloud services 1356, and the control plane VCN 1316 may beisolated from cloud services 1356 that may not be in the same region asthe control plane VCN 1316. For example, the control plane VCN 1316 maybe located in “Region 1,” and cloud service “Deployment 12,” may belocated in Region 1 and in “Region 2.” If a call to Deployment 12 ismade by the service gateway 1336 contained in the control plane VCN 1316located in Region 1, the call may be transmitted to Deployment 12 inRegion 1. In this example, the control plane VCN 1316, or Deployment 12in Region 1, may not be communicatively coupled to, or otherwise incommunication with, Deployment 12 in Region 2.

FIG. 14 is a block diagram 1400 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1402 (e.g. service operators 1202 of FIG. 12 ) can becommunicatively coupled to a secure host tenancy 1404 (e.g. the securehost tenancy 1204 of FIG. 12 ) that can include a virtual cloud network(VCN) 1406 (e.g. the VCN 1206 of FIG. 12 ) and a secure host subnet 1408(e.g. the secure host subnet 1208 of FIG. 12 ). The VCN 1406 can includean LPG 1410 (e.g. the LPG 1210 of FIG. 12 ) that can be communicativelycoupled to an SSH VCN 1412 (e.g. the SSH VCN 1212 of FIG. 12 ) via anLPG 1410 contained in the SSH VCN 1412. The SSH VCN 1412 can include anSSH subnet 1414 (e.g. the SSH subnet 1214 of FIG. 12 ), and the SSH VCN1412 can be communicatively coupled to a control plane VCN 1416 (e.g.the control plane VCN 1216 of FIG. 12 ) via an LPG 1410 contained in thecontrol plane VCN 1416 and to a data plane VCN 1418 (e.g. the data plane1218 of FIG. 12 ) via an LPG 1410 contained in the data plane VCN 1418.The control plane VCN 1416 and the data plane VCN 1418 can be containedin a service tenancy 1419 (e.g. the service tenancy 1219 of FIG. 12 ).

The control plane VCN 1416 can include a control plane DMZ tier 1420(e.g. the control plane DMZ tier 1220 of FIG. 12 ) that can include loadbalancer (LB) subnet(s) 1422 (e.g. LB subnet(s) 1222 of FIG. 12 ), acontrol plane app tier 1424 (e.g. the control plane app tier 1224 ofFIG. 12 ) that can include app subnet(s) 1426 (e.g. similar to appsubnet(s) 1226 of FIG. 12 ), a control plane data tier 1428 (e.g. thecontrol plane data tier 1228 of FIG. 12 ) that can include DB subnet(s)1430. The LB subnet(s) 1422 contained in the control plane DMZ tier 1420can be communicatively coupled to the app subnet(s) 1426 contained inthe control plane app tier 1424 and to an Internet gateway 1434 (e.g.the Internet gateway 1234 of FIG. 12 ) that can be contained in thecontrol plane VCN 1416, and the app subnet(s) 1426 can becommunicatively coupled to the DB subnet(s) 1430 contained in thecontrol plane data tier 1428 and to a service gateway 1436 (e.g. theservice gateway of FIG. 12 ) and a network address translation (NAT)gateway 1438 (e.g. the NAT gateway 1238 of FIG. 12 ). The control planeVCN 1416 can include the service gateway 1436 and the NAT gateway 1438.

The data plane VCN 1418 can include a data plane app tier 1446 (e.g. thedata plane app tier 1246 of FIG. 12 ), a data plane DMZ tier 1448 (e.g.the data plane DMZ tier 1248 of FIG. 12 ), and a data plane data tier1450 (e.g. the data plane data tier 1250 of FIG. 12 ). The data planeDMZ tier 1448 can include LB subnet(s) 1422 that can be communicativelycoupled to trusted app subnet(s) 1460 and untrusted app subnet(s) 1462of the data plane app tier 1446 and the Internet gateway 1434 containedin the data plane VCN 1418. The trusted app subnet(s) 1460 can becommunicatively coupled to the service gateway 1436 contained in thedata plane VCN 1418, the NAT gateway 1438 contained in the data planeVCN 1418, and DB subnet(s) 1430 contained in the data plane data tier1450. The untrusted app subnet(s) 1462 can be communicatively coupled tothe service gateway 1436 contained in the data plane VCN 1418 and DBsubnet(s) 1430 contained in the data plane data tier 1450. The dataplane data tier 1450 can include DB subnet(s) 1430 that can becommunicatively coupled to the service gateway 1436 contained in thedata plane VCN 1418.

The untrusted app subnet(s) 1462 can include one or more primary VNICs1464(1)-(N) that can be communicatively coupled to tenant virtualmachines (VMs) 1466(1)-(N). Each tenant VM 1466(1)-(N) can becommunicatively coupled to a respective app subnet 1467(1)-(N) that canbe contained in respective container egress VCNs 1468(1)-(N) that can becontained in respective customer tenancies 1470(1)-(N). Respectivesecondary VNICs 1472(1)-(N) can facilitate communication between theuntrusted app subnet(s) 1462 contained in the data plane VCN 1418 andthe app subnet contained in the container egress VCNs 1468(1)-(N). Eachcontainer egress VCNs 1468(1)-(N) can include a NAT gateway 1438 thatcan be communicatively coupled to public Internet 1454 (e.g. publicInternet 1254 of FIG. 12 ).

The Internet gateway 1434 contained in the control plane VCN 1416 andcontained in the data plane VCN 1418 can be communicatively coupled to ametadata management service 1452 (e.g. the metadata management system1252 of FIG. 12 ) that can be communicatively coupled to public Internet1454. Public Internet 1454 can be communicatively coupled to the NATgateway 1438 contained in the control plane VCN 1416 and contained inthe data plane VCN 1418. The service gateway 1436 contained in thecontrol plane VCN 1416 and contained in the data plane VCN 1418 can becommunicatively couple to cloud services 1456.

In some embodiments, the data plane VCN 1418 can be integrated withcustomer tenancies 1470. This integration can be useful or desirable forcustomers of the IaaS provider in some cases such as a case that maydesire support when executing code. The customer may provide code to runthat may be destructive, may communicate with other customer resources,or may otherwise cause undesirable effects. In response to this, theIaaS provider may determine whether to run code given to the IaaSprovider by the customer.

In some examples, the customer of the IaaS provider may grant temporarynetwork access to the IaaS provider and request a function to beattached to the data plane tier app 1446. Code to run the function maybe executed in the VMs 1466(1)-(N), and the code may not be configuredto run anywhere else on the data plane VCN 1418. Each VM 1466(1)-(N) maybe connected to one customer tenancy 1470. Respective containers1471(1)-(N) contained in the VMs 1466(1)-(N) may be configured to runthe code. In this case, there can be a dual isolation (e.g., thecontainers 1471(1)-(N) running code, where the containers 1471(1)-(N)may be contained in at least the VM 1466(1)-(N) that are contained inthe untrusted app subnet(s) 1462), which may help prevent incorrect orotherwise undesirable code from damaging the network of the IaaSprovider or from damaging a network of a different customer. Thecontainers 1471(1)-(N) may be communicatively coupled to the customertenancy 1470 and may be configured to transmit or receive data from thecustomer tenancy 1470. The containers 1471(1)-(N) may not be configuredto transmit or receive data from any other entity in the data plane VCN1418. Upon completion of running the code, the IaaS provider may kill orotherwise dispose of the containers 1471(1)-(N).

In some embodiments, the trusted app subnet(s) 1460 may run code thatmay be owned or operated by the IaaS provider. In this embodiment, thetrusted app subnet(s) 1460 may be communicatively coupled to the DBsubnet(s) 1430 and be configured to execute CRUD operations in the DBsubnet(s) 1430. The untrusted app subnet(s) 1462 may be communicativelycoupled to the DB subnet(s) 1430, but in this embodiment, the untrustedapp subnet(s) may be configured to execute read operations in the DBsubnet(s) 1430. The containers 1471(1)-(N) that can be contained in theVM 1466(1)-(N) of each customer and that may run code from the customermay not be communicatively coupled with the DB subnet(s) 1430.

In other embodiments, the control plane VCN 1416 and the data plane VCN1418 may not be directly communicatively coupled. In this embodiment,there may be no direct communication between the control plane VCN 1416and the data plane VCN 1418. However, communication can occur indirectlythrough at least one method. An LPG 1410 may be established by the IaaSprovider that can facilitate communication between the control plane VCN1416 and the data plane VCN 1418. In another example, the control planeVCN 1416 or the data plane VCN 1418 can make a call to cloud services1456 via the service gateway 1436. For example, a call to cloud services1456 from the control plane VCN 1416 can include a request for a servicethat can communicate with the data plane VCN 1418.

FIG. 15 is a block diagram 1500 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1502 (e.g. service operators 1202 of FIG. 12 ) can becommunicatively coupled to a secure host tenancy 1504 (e.g. the securehost tenancy 1204 of FIG. 12 ) that can include a virtual cloud network(VCN) 1506 (e.g. the VCN 1206 of FIG. 12 ) and a secure host subnet 1508(e.g. the secure host subnet 1208 of FIG. 12 ). The VCN 1506 can includean LPG 1510 (e.g. the LPG 1210 of FIG. 12 ) that can be communicativelycoupled to an SSH VCN 1512 (e.g. the SSH VCN 1212 of FIG. 12 ) via anLPG 1510 contained in the SSH VCN 1512. The SSH VCN 1512 can include anSSH subnet 1514 (e.g. the SSH subnet 1214 of FIG. 12 ), and the SSH VCN1512 can be communicatively coupled to a control plane VCN 1516 (e.g.the control plane VCN 1216 of FIG. 12 ) via an LPG 1510 contained in thecontrol plane VCN 1516 and to a data plane VCN 1518 (e.g. the data plane1218 of FIG. 12 ) via an LPG 1510 contained in the data plane VCN 1518.The control plane VCN 1516 and the data plane VCN 1518 can be containedin a service tenancy 1519 (e.g. the service tenancy 1219 of FIG. 12 ).

The control plane VCN 1516 can include a control plane DMZ tier 1520(e.g. the control plane DMZ tier 1220 of FIG. 12 ) that can include LBsubnet(s) 1522 (e.g. LB subnet(s) 1222 of FIG. 12 ), a control plane apptier 1524 (e.g. the control plane app tier 1224 of FIG. 12 ) that caninclude app subnet(s) 1526 (e.g. app subnet(s) 1226 of FIG. 12 ), acontrol plane data tier 1528 (e.g. the control plane data tier 1228 ofFIG. 12 ) that can include DB subnet(s) 1530 (e.g. DB subnet(s) 1430 ofFIG. 14 ). The LB subnet(s) 1522 contained in the control plane DMZ tier1520 can be communicatively coupled to the app subnet(s) 1526 containedin the control plane app tier 1524 and to an Internet gateway 1534 (e.g.the Internet gateway 1234 of FIG. 12 ) that can be contained in thecontrol plane VCN 1516, and the app subnet(s) 1526 can becommunicatively coupled to the DB subnet(s) 1530 contained in thecontrol plane data tier 1528 and to a service gateway 1536 (e.g. theservice gateway of FIG. 12 ) and a network address translation (NAT)gateway 1538 (e.g. the NAT gateway 1238 of FIG. 12 ). The control planeVCN 1516 can include the service gateway 1536 and the NAT gateway 1538.

The data plane VCN 1518 can include a data plane app tier 1546 (e.g. thedata plane app tier 1246 of FIG. 12 ), a data plane DMZ tier 1548 (e.g.the data plane DMZ tier 1248 of FIG. 12 ), and a data plane data tier1550 (e.g. the data plane data tier 1250 of FIG. 12 ). The data planeDMZ tier 1548 can include LB subnet(s) 1522 that can be communicativelycoupled to trusted app subnet(s) 1560 (e.g. trusted app subnet(s) 1460of FIG. 14 ) and untrusted app subnet(s) 1562 (e.g. untrusted appsubnet(s) 1462 of FIG. 14 ) of the data plane app tier 1546 and theInternet gateway 1534 contained in the data plane VCN 1518. The trustedapp subnet(s) 1560 can be communicatively coupled to the service gateway1536 contained in the data plane VCN 1518, the NAT gateway 1538contained in the data plane VCN 1518, and DB subnet(s) 1530 contained inthe data plane data tier 1550. The untrusted app subnet(s) 1562 can becommunicatively coupled to the service gateway 1536 contained in thedata plane VCN 1518 and DB subnet(s) 1530 contained in the data planedata tier 1550. The data plane data tier 1550 can include DB subnet(s)1530 that can be communicatively coupled to the service gateway 1536contained in the data plane VCN 1518.

The untrusted app subnet(s) 1562 can include primary VNICs 1564(1)-(N)that can be communicatively coupled to tenant virtual machines (VMs)1566(1)-(N) residing within the untrusted app subnet(s) 1562. Eachtenant VM 1566(1)-(N) can run code in a respective container1567(1)-(N), and be communicatively coupled to an app subnet 1526 thatcan be contained in a data plane app tier 1546 that can be contained ina container egress VCN 1568. Respective secondary VNICs 1572(1)-(N) canfacilitate communication between the untrusted app subnet(s) 1562contained in the data plane VCN 1518 and the app subnet contained in thecontainer egress VCN 1568. The container egress VCN can include a NATgateway 1538 that can be communicatively coupled to public Internet 1554(e.g. public Internet 1254 of FIG. 12 ).

The Internet gateway 1534 contained in the control plane VCN 1516 andcontained in the data plane VCN 1518 can be communicatively coupled to ametadata management service 1552 (e.g. the metadata management system1252 of FIG. 12 ) that can be communicatively coupled to public Internet1554. Public Internet 1554 can be communicatively coupled to the NATgateway 1538 contained in the control plane VCN 1516 and contained inthe data plane VCN 1518. The service gateway 1536 contained in thecontrol plane VCN 1516 and contained in the data plane VCN 1518 can becommunicatively couple to cloud services 1556.

In some examples, the pattern illustrated by the architecture of blockdiagram 1500 of FIG. 15 may be considered an exception to the patternillustrated by the architecture of block diagram 1400 of FIG. 14 and maybe desirable for a customer of the IaaS provider if the IaaS providercannot directly communicate with the customer (e.g., a disconnectedregion). The respective containers 1567(1)-(N) that are contained in theVMs 1566(1)-(N) for each customer can be accessed in real-time by thecustomer. The containers 1567(1)-(N) may be configured to make calls torespective secondary VNICs 1572(1)-(N) contained in app subnet(s) 1526of the data plane app tier 1546 that can be contained in the containeregress VCN 1568. The secondary VNICs 1572(1)-(N) can transmit the callsto the NAT gateway 1538 that may transmit the calls to public Internet1554. In this example, the containers 1567(1)-(N) that can be accessedin real-time by the customer can be isolated from the control plane VCN1516 and can be isolated from other entities contained in the data planeVCN 1518. The containers 1567(1)-(N) may also be isolated from resourcesfrom other customers.

In other examples, the customer can use the containers 1567(1)-(N) tocall cloud services 1556. In this example, the customer may run code inthe containers 1567(1)-(N) that requests a service from cloud services1556. The containers 1567(1)-(N) can transmit this request to thesecondary VNICs 1572(1)-(N) that can transmit the request to the NATgateway that can transmit the request to public Internet 1554. PublicInternet 1554 can transmit the request to LB subnet(s) 1522 contained inthe control plane VCN 1516 via the Internet gateway 1534. In response todetermining the request is valid, the LB subnet(s) can transmit therequest to app subnet(s) 1526 that can transmit the request to cloudservices 1556 via the service gateway 1536.

It should be appreciated that IaaS architectures 1200, 1300, 1400, 1500depicted in the figures may have other components than those depicted.Further, the embodiments shown in the figures are only some examples ofa cloud infrastructure system that may incorporate an embodiment of thedisclosure. In some other embodiments, the IaaS systems may have more orfewer components than shown in the figures, may combine two or morecomponents, or may have a different configuration or arrangement ofcomponents.

In certain embodiments, the IaaS systems described herein may include asuite of applications, middleware, and database service offerings thatare delivered to a customer in a self-service, subscription-based,elastically scalable, reliable, highly available, and secure manner. Anexample of such an IaaS system is the Oracle Cloud Infrastructure (OCI)provided by the present assignee.

FIG. 16 illustrates an example computer system 1600, in which variousembodiments may be implemented. The system 1600 may be used to implementany of the computer systems described above. As shown in the figure,computer system 1600 includes a processing unit 1604 that communicateswith a number of peripheral subsystems via a bus subsystem 1602. Theseperipheral subsystems may include a processing acceleration unit 1606,an I/O subsystem 1608, a storage subsystem 1618 and a communicationssubsystem 1624. Storage subsystem 1618 includes tangiblecomputer-readable storage media 1622 and a system memory 1610.

Bus subsystem 1602 provides a mechanism for letting the variouscomponents and subsystems of computer system 1600 communicate with eachother as intended. Although bus subsystem 1602 is shown schematically asa single bus, alternative embodiments of the bus subsystem may utilizemultiple buses. Bus subsystem 1602 may be any of several types of busstructures including a memory bus or memory controller, a peripheralbus, and a local bus using any of a variety of bus architectures. Forexample, such architectures may include an Industry StandardArchitecture (ISA) bus, Micro Channel Architecture (MCA) bus, EnhancedISA (EISA) bus, Video Electronics Standards Association (VESA) localbus, and Peripheral Component Interconnect (PCI) bus, which can beimplemented as a Mezzanine bus manufactured to the IEEE P1386.1standard.

Processing unit 1604, which can be implemented as one or more integratedcircuits (e.g., a conventional microprocessor or microcontroller),controls the operation of computer system 1600. One or more processorsmay be included in processing unit 1604. These processors may includesingle core or multicore processors. In certain embodiments, processingunit 1604 may be implemented as one or more independent processing units1632 and/or 1634 with single or multicore processors included in eachprocessing unit. In other embodiments, processing unit 1604 may also beimplemented as a quad-core processing unit formed by integrating twodual-core processors into a single chip.

In various embodiments, processing unit 1604 can execute a variety ofprograms in response to program code and can maintain multipleconcurrently executing programs or processes. At any given time, some orall of the program code to be executed can be resident in processor(s)1604 and/or in storage subsystem 1618. Through suitable programming,processor(s) 1604 can provide various functionalities described above.Computer system 1600 may additionally include a processing accelerationunit 1606, which can include a digital signal processor (DSP), aspecial-purpose processor, and/or the like.

I/O subsystem 1608 may include user interface input devices and userinterface output devices. User interface input devices may include akeyboard, pointing devices such as a mouse or trackball, a touchpad ortouch screen incorporated into a display, a scroll wheel, a click wheel,a dial, a button, a switch, a keypad, audio input devices with voicecommand recognition systems, microphones, and other types of inputdevices. User interface input devices may include, for example, motionsensing and/or gesture recognition devices such as the Microsoft Kinect®motion sensor that enables users to control and interact with an inputdevice, such as the Microsoft Xbox® 360 game controller, through anatural user interface using gestures and spoken commands. Userinterface input devices may also include eye gesture recognition devicessuch as the Google Glass® blink detector that detects eye activity(e.g., ‘blinking’ while taking pictures and/or making a menu selection)from users and transforms the eye gestures as input into an input device(e.g., Google Glass®). Additionally, user interface input devices mayinclude voice recognition sensing devices that enable users to interactwith voice recognition systems (e.g., Siri® navigator), through voicecommands.

User interface input devices may also include, without limitation, threedimensional (3D) mice, joysticks or pointing sticks, gamepads andgraphic tablets, and audio/visual devices such as speakers, digitalcameras, digital camcorders, portable media players, webcams, imagescanners, fingerprint scanners, barcode reader 3D scanners, 3D printers,laser rangefinders, and eye gaze tracking devices. Additionally, userinterface input devices may include, for example, medical imaging inputdevices such as computed tomography, magnetic resonance imaging,position emission tomography, medical ultrasonography devices. Userinterface input devices may also include, for example, audio inputdevices such as MIDI keyboards, digital musical instruments and thelike.

User interface output devices may include a display subsystem, indicatorlights, or non-visual displays such as audio output devices, etc. Thedisplay subsystem may be a cathode ray tube (CRT), a flat-panel device,such as that using a liquid crystal display (LCD) or plasma display, aprojection device, a touch screen, and the like. In general, use of theterm “output device” is intended to include all possible types ofdevices and mechanisms for outputting information from computer system1600 to a user or other computer. For example, user interface outputdevices may include, without limitation, a variety of display devicesthat visually convey text, graphics and audio/video information such asmonitors, printers, speakers, headphones, automotive navigation systems,plotters, voice output devices, and modems.

Computer system 1600 may comprise a storage subsystem 1618 thatcomprises software elements, shown as being currently located within asystem memory 1610. System memory 1610 may store program instructionsthat are loadable and executable on processing unit 1604, as well asdata generated during the execution of these programs.

Depending on the configuration and type of computer system 1600, systemmemory 1610 may be volatile (such as random access memory (RAM)) and/ornon-volatile (such as read-only memory (ROM), flash memory, etc.) TheRAM typically contains data and/or program modules that are immediatelyaccessible to and/or presently being operated and executed by processingunit 1604. In some implementations, system memory 1610 may includemultiple different types of memory, such as static random access memory(SRAM) or dynamic random access memory (DRAM). In some implementations,a basic input/output system (BIOS), containing the basic routines thathelp to transfer information between elements within computer system1600, such as during start-up, may typically be stored in the ROM. Byway of example, and not limitation, system memory 1610 also illustratesapplication programs 1612, which may include client applications, Webbrowsers, mid-tier applications, relational database management systems(RDBMS), etc., program data 1614, and an operating system 1616. By wayof example, operating system 1616 may include various versions ofMicrosoft Windows®, Apple Macintosh®, and/or Linux operating systems, avariety of commercially-available UNIX® or UNIX-like operating systems(including without limitation the variety of GNU/Linux operatingsystems, the Google Chromed OS, and the like) and/or mobile operatingsystems such as iOS, Windows® Phone, Android® OS, BlackBerry® 16 OS, andPalm® OS operating systems.

Storage subsystem 1618 may also provide a tangible computer-readablestorage medium for storing the basic programming and data constructsthat provide the functionality of some embodiments. Software (programs,code modules, instructions) that when executed by a processor providethe functionality described above may be stored in storage subsystem1618. These software modules or instructions may be executed byprocessing unit 1604. Storage subsystem 1618 may also provide arepository for storing data used in accordance with the presentdisclosure.

Storage subsystem 1600 may also include a computer-readable storagemedia reader 1620 that can further be connected to computer-readablestorage media 1622. Together and, optionally, in combination with systemmemory 1610, computer-readable storage media 1622 may comprehensivelyrepresent remote, local, fixed, and/or removable storage devices plusstorage media for temporarily and/or more permanently containing,storing, transmitting, and retrieving computer-readable information.

Computer-readable storage media 1622 containing code, or portions ofcode, can also include any appropriate media known or used in the art,including storage media and communication media, such as but not limitedto, volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage and/or transmissionof information. This can include tangible computer-readable storagemedia such as RAM, ROM, electronically erasable programmable ROM(EEPROM), flash memory or other memory technology, CD-ROM, digitalversatile disk (DVD), or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or other tangible computer readable media. This can also includenontangible computer-readable media, such as data signals, datatransmissions, or any other medium which can be used to transmit thedesired information and which can be accessed by computing system 1600.

By way of example, computer-readable storage media 1622 may include ahard disk drive that reads from or writes to non-removable, nonvolatilemagnetic media, a magnetic disk drive that reads from or writes to aremovable, nonvolatile magnetic disk, and an optical disk drive thatreads from or writes to a removable, nonvolatile optical disk such as aCD ROM, DVD, and Blu-Ray® disk, or other optical media.Computer-readable storage media 1622 may include, but is not limited to,Zip® drives, flash memory cards, universal serial bus (USB) flashdrives, secure digital (SD) cards, DVD disks, digital video tape, andthe like. Computer-readable storage media 1622 may also include,solid-state drives (SSD) based on non-volatile memory such asflash-memory based SSDs, enterprise flash drives, solid state ROM, andthe like, SSDs based on volatile memory such as solid state RAM, dynamicRAM, static RAM, DRAM-based SSDs, magnetoresistive RAM (MRAM) SSDs, andhybrid SSDs that use a combination of DRAM and flash memory based SSDs.The disk drives and their associated computer-readable media may providenon-volatile storage of computer-readable instructions, data structures,program modules, and other data for computer system 1600.

Communications subsystem 1624 provides an interface to other computersystems and networks. Communications subsystem 1624 serves as aninterface for receiving data from and transmitting data to other systemsfrom computer system 1600. For example, communications subsystem 1624may enable computer system 1600 to connect to one or more devices viathe Internet. In some embodiments communications subsystem 1624 caninclude radio frequency (RF) transceiver components for accessingwireless voice and/or data networks (e.g., using cellular telephonetechnology, advanced data network technology, such as 3G, 4G or EDGE(enhanced data rates for global evolution), WiFi (IEEE 802.11 familystandards, or other mobile communication technologies, or anycombination thereof), global positioning system (GPS) receivercomponents, and/or other components. In some embodiments communicationssubsystem 1624 can provide wired network connectivity (e.g., Ethernet)in addition to or instead of a wireless interface.

In some embodiments, communications subsystem 1624 may also receiveinput communication in the form of structured and/or unstructured datafeeds 1626, event streams 1628, event updates 1630, and the like onbehalf of one or more users who may use computer system 1600.

By way of example, communications subsystem 1624 may be configured toreceive data feeds 1626 in real-time from users of social networksand/or other communication services such as Twitter® feeds, Facebook®updates, web feeds such as Rich Site Summary (RSS) feeds, and/orreal-time updates from one or more third party information sources.

Additionally, communications subsystem 1624 may also be configured toreceive data in the form of continuous data streams, which may includeevent streams 1628 of real-time events and/or event updates 1630 thatmay be continuous or unbounded in nature with no explicit end. Examplesof applications that generate continuous data may include, for example,sensor data applications, financial tickers, network performancemeasuring tools (e.g. network monitoring and traffic managementapplications), clickstream analysis tools, automobile trafficmonitoring, and the like.

Communications subsystem 1624 may also be configured to output thestructured and/or unstructured data feeds 1626, event streams 1628,event updates 1630, and the like to one or more databases that may be incommunication with one or more streaming data source computers coupledto computer system 1600.

Computer system 1600 can be one of various types, including a handheldportable device (e.g., an iPhone® cellular phone, an iPad® computingtablet, a PDA), a wearable device (e.g., a Google Glass® head mounteddisplay), a PC, a workstation, a mainframe, a kiosk, a server rack, orany other data processing system.

Due to the ever-changing nature of computers and networks, thedescription of computer system 1600 depicted in the figure is intendedonly as a specific example. Many other configurations having more orfewer components than the system depicted in the figure are possible.For example, customized hardware might also be used and/or particularelements might be implemented in hardware, firmware, software (includingapplets), or a combination. Further, connection to other computingdevices, such as network input/output devices, may be employed. Based onthe disclosure and teachings provided herein, a person of ordinary skillin the art will appreciate other ways and/or methods to implement thevarious embodiments.

Although specific embodiments have been described, variousmodifications, alterations, alternative constructions, and equivalentsare also encompassed within the scope of the disclosure. Embodiments arenot restricted to operation within certain specific data processingenvironments, but are free to operate within a plurality of dataprocessing environments. Additionally, although embodiments have beendescribed using a particular series of transactions and steps, it shouldbe apparent to those skilled in the art that the scope of the presentdisclosure is not limited to the described series of transactions andsteps. Various features and aspects of the above-described embodimentsmay be used individually or jointly.

Further, while embodiments have been described using a particularcombination of hardware and software, it should be recognized that othercombinations of hardware and software are also within the scope of thepresent disclosure. Embodiments may be implemented only in hardware, oronly in software, or using combinations thereof. The various processesdescribed herein can be implemented on the same processor or differentprocessors in any combination. Accordingly, where components or modulesare described as being configured to perform certain operations, suchconfiguration can be accomplished, e.g., by designing electroniccircuits to perform the operation, by programming programmableelectronic circuits (such as microprocessors) to perform the operation,or any combination thereof. Processes can communicate using a variety oftechniques including but not limited to conventional techniques forinter process communication, and different pairs of processes may usedifferent techniques, or the same pair of processes may use differenttechniques at different times.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. It will, however, beevident that additions, subtractions, deletions, and other modificationsand changes may be made thereunto without departing from the broaderspirit and scope as set forth in the claims. Thus, although specificdisclosure embodiments have been described, these are not intended to belimiting. Various modifications and equivalents are within the scope ofthe following claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the disclosed embodiments (especially in thecontext of the following claims) are to be construed to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms (i.e., meaning“including, but not limited to,”) unless otherwise noted. The term“connected” is to be construed as partly or wholly contained within,attached to, or joined together, even if there is something intervening.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate embodiments and does not pose alimitation on the scope of the disclosure unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the disclosure.

Disjunctive language such as the phrase “at least one of X, Y, or Z,”unless specifically stated otherwise, is intended to be understoodwithin the context as used in general to present that an item, term,etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y,and/or Z). Thus, such disjunctive language is not generally intended to,and should not, imply that certain embodiments require at least one ofX, at least one of Y, or at least one of Z to each be present.

Preferred embodiments of this disclosure are described herein, includingthe best mode known for carrying out the disclosure. Variations of thosepreferred embodiments may become apparent to those of ordinary skill inthe art upon reading the foregoing description. Those of ordinary skillshould be able to employ such variations as appropriate and thedisclosure may be practiced otherwise than as specifically describedherein. Accordingly, this disclosure includes all modifications andequivalents of the subject matter recited in the claims appended heretoas permitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the disclosure unless otherwise indicated herein.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein. In the foregoing specification, aspects of the disclosure aredescribed with reference to specific embodiments thereof, but thoseskilled in the art will recognize that the disclosure is not limitedthereto. Various features and aspects of the above-described disclosuremay be used individually or jointly. Further, embodiments can beutilized in any number of environments and applications beyond thosedescribed herein without departing from the broader spirit and scope ofthe specification. The specification and drawings are, accordingly, tobe regarded as illustrative rather than restrictive.

What is claimed is:
 1. A method comprising: storing, for each hostmachine of a plurality of host machines, hierarchical localityinformation for the host machine, the hierarchical locality informationfor a host machine identifying, for each of a plurality of hierarchicallevels, location information for the host machine; and responsive toreceiving a request requesting execution of a workload: obtaining thehierarchical locality information for the plurality of host machines,and providing the hierarchical locality information of the plurality ofhost machines as a response to the request.
 2. The method of claim 1,wherein the plurality of hierarchical levels includes a rack locality, ablock locality, a building locality, and an available domain locality.3. The method of claim 2, wherein the location information for eachhierarchical level of the plurality of hierarchical levels includes anidentifier of the hierarchical level.
 4. The method of claim 1, furthercomprising: generating an encoded array comprising the hierarchicallocality information for the host machine, the encoded array comprisinga plurality of hash blocks, each of which includes encoded locationinformation for a particular locality.
 5. The method of claim 4, whereinthe encoded array includes: (i) a first hash block including hash of arack identifier of a rack comprising the host machine, and a customeridentifier, (ii) a second hash block including hash of a blockidentifier of a block comprising the rack and the customer identifier,(iii) a third hash block including hash of a building identifier of abuilding comprising the block and the customer identifier, and (iv) afourth hash block including hash of a domain identifier of a domaincomprising the building and the customer identifier.
 6. The method ofclaim 1, further comprising: receiving, by a customer, the hierarchicallocality information of the plurality of host machines; selecting one ormore host machines from the plurality of host machines for executing aworkload, the selecting being performed based on one or more constraintsassociated with the workload; and executing the workload on the one ormore host machines.
 7. The method of claim 6, wherein one or moreconstraints includes a first constraint corresponding to a latencythreshold associated with the workload and a second constraintassociated with a desired degree of availability in executing theworkload.
 8. The method of claim 1, wherein the hierarchical localityinformation for the host machine is obtained from an instance metadataservice, the hierarchical locality information being stored in the hostmachine by the instance metadata service via a network virtualizationdevice associated with the host machine.
 9. A computer-readable mediumstoring computer-executable instructions that, when executed by one ormore processors, cause: storing, for each host machine of a plurality ofhost machines, hierarchical locality information for the host machine,the hierarchical locality information for a host machine identifying,for each of a plurality of hierarchical levels, location information forthe host machine; and responsive to receiving a request requestingexecution of a workload, obtaining the hierarchical locality informationfor the plurality of host machines; and providing the hierarchicallocality information of the plurality of host machines as a response tothe request.
 10. The computer-readable medium storingcomputer-executable instructions of claim 9, wherein the plurality ofhierarchical levels includes a rack locality, a block locality, abuilding locality, and an available domain locality.
 11. Thecomputer-readable medium storing computer-executable instructions ofclaim 10, wherein the location information for each hierarchical levelof the plurality of hierarchical levels includes an identifier of thehierarchical level.
 12. The computer-readable medium storingcomputer-executable instructions of claim 9, wherein the instructionsfurther comprise instructions that, when executed by one or moreprocessors, cause: generating an encoded array comprising thehierarchical locality information for the host machine, the encodedarray comprising a plurality of hash blocks, each of which includesencoded location information for a particular locality.
 13. Thecomputer-readable medium storing computer-executable instructions ofclaim 12, wherein the encoded array includes: (i) a first hash blockincluding hash of a rack identifier of a rack comprising the hostmachine, and a customer identifier, (ii) a second hash block includinghash of a block identifier of a block comprising the rack and thecustomer identifier, (iii) a third hash block including hash of abuilding identifier of a building comprising the block and the customeridentifier, and (iv) a fourth hash block including hash of a domainidentifier of a domain comprising the building and the customeridentifier.
 14. The computer-readable medium storing computer-executableinstructions of claim 9, wherein the instructions further compriseinstructions that, when executed by one or more processors, cause:receiving, by a customer, the hierarchical locality information of theplurality of host machines; selecting one or more host machines from theplurality of host machines for executing a workload, the selecting beingperformed based on one or more constraints associated with the workload;and executing the workload on the one or more host machines.
 15. Thecomputer-readable medium storing computer-executable instructions ofclaim 14, wherein one or more constraints includes a first constraintcorresponding to a latency threshold associated with the workload and asecond constraint associated with a desired degree of availability inexecuting the workload.
 16. The computer-readable medium storingcomputer-executable instructions of claim 9, wherein the hierarchicallocality information for the host machine is obtained from an instancemetadata service, the hierarchical locality information being stored inthe host machine by the instance metadata service via a networkvirtualization device associated with the host machine.
 17. A computingdevice comprising: a processor; and a memory including instructionsthat, when executed with the processor, cause the computing device to,at least: store, for each host machine of a plurality of host machines,hierarchical locality information for the host machine, the hierarchicallocality information for a host machine identifying, for each of aplurality of hierarchical levels, location information for the hostmachine; and responsive to receiving a request requesting execution of aworkload: obtain the hierarchical locality information for the pluralityof host machines, and provide the hierarchical locality information ofthe plurality of host machines in response to the request.
 18. Thecomputing device of claim 17, wherein the plurality of hierarchicallevels includes a rack locality, a block locality, a building locality,and an available domain locality.
 19. The computing device of claim 17,wherein the location information for each hierarchical level of theplurality of hierarchical levels includes an identifier of thehierarchical level.
 20. The computing device of claim 17, furtherconfigured to: generate an encoded array comprising the hierarchicallocality information for the host machine, the encoded array comprisinga plurality of hash blocks, each of which includes encoded locationinformation for a particular locality.